Abstract: To investigate effects of different tillage practices on nitrogen loss process in red soil sloping farmland, as well as intrinsic mechanisms, four treatment plots were established including downslope ridge tillage（DT treatment）, cross-slope ridge tillage（RT treatment）, plastic film mulching without ridging（PM treatment）, and conventional tillage without ridging（CT treatment）．Laboratory-scale artificial rainfall simulation experiments were conducted．Results has indicated that tillage practices and rainfall intensity exert significant effects on both runoff and sediment yield as well as nitrogen loss process．Regarding runoff process, PM and DT treatments were mainly characterized by surface runoff, whereas RT and CT were dominated by subsurface flow．Surface runoff volumes across four treatments followed the order PM > DT > CT > RT, whereas the pattern for subsurface flow was the opposite．Regarding sediment yield, four treatments exhibited the following order of erosion sediment yield: DT > CT > RT > PM．Total sediment yield in DT treatment was significantly higher than that in other treatments, ranging from 2.17 to 6.33 times higher．Under different rainfall intensities, total nitrogen loss across four treatments followed order: RT > CT > DT > PM, with PM treatment significantly reducing nitrogen loss．In terms of total nitrogen loss, surface runoff, percolate, and eroded sediment accounted for 24.76%, 70.68%, and 4.57%, respectively; for nitrate nitrogen loss, these proportions were 21.24%, 78.56%, and 0.20%, while proportions of ammonium nitrogen loss were 52.50%, 22.61%, and 24.89%, respectively．Surface runoff and subsurface flow are main pathways for nitrogen loss from red soil sloping farmland．Among these, total nitrogen and nitrate nitrogen are mainly lost through subsurface flow/leaching, while ammonium nitrogen is mainly lost via surface runoff．PM treatment significantly reduces sediment erosion and nitrogen loss levels．It is recommended that PM tillage system be prioritized for promotion in the cultivation management of red soil slope farmland．