The effects of straw returning on crop yield and soil nutrients under rice-rapeseed rotation were studied，so as to provide technical parameters for the mechanization of straw returning，and provide reference for the coordinated development of high yield and soil fertility.In this study，the comparative positioning experiment of straw returning to the field was carried out during 2017—2019 in Wuxue city，Hubei province.Field experiments of straw returning were conducted in the rice-rapeseed rotation farming area of the middle reaches of the Yangtze River from 2017 to 2019.Four treatments were set up:no stubblein+fine grinding，middle stubblein+fine grinding，middle stubblein+coarse grinding and high stubblein+fine grinding.The effects of straw returning to the field on the growth and yield of rice and rapeseed，and soil nutrients under different stubblein heights and grinding degrees were studied.The results showed that the higher the stubblein height was，the better it was to improve the basic seedlings，and it was higher in coarse grinding than that in fine grinding both in rice and rapeseed seasons.Different stubblein height and straw grinding degree had no significant effect on the SPAD value at seedling stage.In the first season，the yield with medium stubble was higher than that without stubble and with high stubble(the yield increment of rice and rapeseed was 7.1%-21.1% and 2.4%-4.6%，respectively)，and that of fine grinding was higher than that of coarse grinding(the increment was 11.7% and 12.9%).However，the yield difference in the second season between the treatments was not significant.During the crop growth period，the soil nutrient content decreased first and increased slightly in the harvest period.In the early stage of crop growth，no stubblein+fine grinding in rice season and middle stubblein+coarse grinding in rapeseed season increased the content of ammonium nitrogen and nitrate nitrogen.In the harvest period，the contents of available phosphorus and available potassium in both rice and rapeseed seasons were higher in middle stubblein+coarse grinding.Therefore，on the basis of yield response and soil nutrient change，considering the operation cost and energy consumption of straw returning to the field，this study recommends that the annual straw returning mode of rice-rapeseed rotation in the middle reaches of the Yangtze River should be rice with middle stubblein，rapeseed with middle or high stubblein，and the straw grinding degree should be fine grinding.