Abstract: Root distribution characteristics of greenhouse cucumber were analyzed using simulated soil column culture method and farmland research. The results show that irrigation under plastic film mulch and drip irrigation yield the highest cucumber root dry weight at 180 d and 210 d after planting, but root dry weight is 29% higher under drip irrigation at harvest. There is significant difference in vertical distribution of cucumber root at different growth periods between drip irrigation and irrigation under plastic film mulch. Before initial fruit appearance stage, the difference in root dry weight is insignificant below 20 cm depth of soil, while root dry weight under irrigation with plastic film mulch treatment is higher than that under drip irrigation at 0～20 cm depth. After abundant fruit stage, root dry weight difference between two irrigation patterns is insignificant at 0～20 cm depth, but root dry weight of drip irrigation is significantly higher than irrigation under plastic film mulch below 20 cm. Cucumber root horizontal distribution is mainly in the 0～15 cm, accounting for 96.6% and 94.2% of total root weight for two irrigation patterns. With the growth of the cucumber plant, inner root distribution gradually decreases from 61.1% to 15.6% of total root amount from before fruit appearance stage to mid or late fruit stage for irrigation under plastic film mulch. The inner and outer root distribution balances out during cucumber growth period under drip irrigation.