Abstract: There are over 4 000 000 hm² medium and low-yield fields in the Huaibei Plain with lime concretion black soil and the easy-dry and easy-water-logged areas formerly flooded by the Yellow River with sand and saline-alkali soil. This region is located at the border lands of 4 provinces, including North Anhui, North Jiangsu, Southwest Shandong and Southeast Henan. This region is located in South Huanghuai (the transition zone from north to south of China), there is preferably warm temperature, moderate rainfall and other nature resources. But as the region is far away from developed economy regions and traffic inconveniences, scientific and technological culture as well social and economic developments have relatively lagged behind. This has resulted in the non-realization of full high agricultural yield potential in the region. Speeding up the transformation of medium and low yields and building new granary in South Huanghuai could increase grain production by 5×10⁹ kg. This will be crucial for the development of modern agriculture and food security in China. Based on global warming, climate change, tend in modern agriculture, green farming and increasing yield quality and efficiency, development strategy of modern agriculture in South Huanghuai was suggested. For crop farming, breeding of new varieties with good resistance to wheat scab and alleviation of wheat scab damage by comprehensive control measures can increase and stabilize grain production and food security. The breeding and amplification of new maize variety with good drought resistance, water-logging tolerance and quick dehydration trait that suit grain harvest by mechanization can increase and stabilize grain production and food security. The expansion of ton-grain-field can ensure food security in South Huanghuai and in China at large. For regional governance, improvement of medium-to-low yields in the Huaibei Plain in lime concretion black soils and in easy-dry and easy-water-logged areas formerly flooded by the Yellow River with sand and saline-alkali soils along with strengthening investment in filed irrigation and drainage systems, building high standard fields assorted well by forest network, road and water channels and wells to ensure stable yield despite drought or excessive rain can increase and stabilize grain production and food security. For modern science and technology, increasing subsidy for agricultural machinery, augmenting the amount of large and medium agricultural machinery, strengthening deep plough and deep scarification and popularizing whole mechanization farming courses will increase and stabilize grain production and food security. For green farming production and quality and efficiency enhancement, pursuing active reduction in the utilization of chemical fertilizers and pesticides, expanding utilization of green bio-fertilizers and other pharmaceuticals that are environment friendly, intensifying efficiency of straw turnover and cycle utilization with bio-resources will increase and stabilize grain production and food security. For sci-tech education, expanding the scale of vocational education, training intellectual peasants and professional services workers, building specialized contingencies for social service will be beneficial for increasing and stabilizing grain production and food security. For regional economic development, growing stronger and larger grain brands in North Anhui; expanding production scale of grains, breeding new modern industry in North Jiangsu; completing synergy-efficient development of agriculture, forestry and animal husbandry in Southwest Shandong; forging flagship of deep-processed Chinese foods in Southeast Henan will increase and stabilize grain production and food security. For agricultural information construction, accelerating popularization of internet, driving quick development of contract farming, export-sales farming and sightseeing agriculture will increase and stabilize grain production and food security. It was suggested that the key sci-tech projects for the "Second Granary" in South Huanghuai should be launched early by the nation. This can promote major grain production areas and economic-sinking areas to become national big granaries, new agricultural economy areas, environmentally graceful areas and sustainable development areas in China.