Abstract: The straw pyrolysis project is an ecological production project designed to convert high quality agricultural straw waste into gas, carbon, oil, and liquid. It has an important practical significance for conserving national energy and reducing emissions in the China's agricultural fields. It has been an important scientific basis to accurately estimate the ecological value of the straw pyrolysis project and provides a systematic and comprehensive quantitative evaluation index system and calculation method to effectively promote green development in agriculture. This paper analyzed the ecological value composition of straw pyrolysis engineering based on the dichotomy theory of ecological value theory. It was concluded that the main ecological beneficial assets generated by the project of straw pyrolysis project were emission reduction and waste resource commercialization. The general formula for estimating the ecological value of straw pyrolysis project established was the ecological value of straw pyrolysis and the gasification project (V_PE)=the monetary value of straw pyrolysis project emission reduction (V_EB) + the economic value of straw resource products (V_RC). In the calculation process, the life cycle analysis (LCA) method was selected to measure the net emission reduction of the straw pyrolysis project, and then the net emission reduction was valued with the help of carbon dioxide shadow prices to obtain the project's emission reduction (V_EB). Furthermore, the economic value of straw resource products achieved by the ecological production project (V_RC) was calculated. Finally, V_EB and V_RC were included to obtain the ecological value of straw pyrolysis and gasification engineering (V_PE). The method was designed using the literature research method to analyze the parameter selection required by each calculation link, and the parameter system required for the calculation process was provided. This study attempted to achieve substantial breakthroughs and innovations during the integration of both method and parameter research in the following three aspects:firstly, the ecological value estimation model of straw pyrolysis project was constructed; not limited to analysis and research from the emission reduction benefits perspective, with a more systematic and comprehensive ecological value estimation method and its required parameter system was established. Secondly, the potential value of the project should be reasonably converted into the "real market value"; in this study, the ecological benefits of the straw pyrolysis project were monetarily priced and measured. Thirdly, this study considered the impact of different technological levels and product energy conversion rates on greenhouse gas emissions during the process of estimating the displacement reduction of end-use energy products. Throughout the study, the general idea of "scientific modelling, reasonable pricing, and accurate estimation" was followed to provide a reliable foundation and support the decision to formulate the national energy saving and emission reduction plans.