Abstract: In order to understand wheat leaf growth in dryland,the parameters of APSIM (agricultural production systen simulator) model were firstly modified and then the dynamical process of leaf area index (LAI) change during wheat growth stage was simulated under different tillage measures,namely,Conventional tillage,Conventional tillage + Stubble retention,No-tillage,No-tillage + straw mulching,Conventional tillage + Plastic film mulching,No-tillage+Plastic film mulching(T,TS,NT,NTS,TP,and NTP). APSIM model was tested according to the data collected from field experiment in Dingxi and the dynamics of LAI on wheat was analysised under different tillage treaments. The results showed that APSIM model can be used to simulate the LAI on wheat under different tillage systems. The predicted and observed LAI were positively correlated (R>0.9) with variation of -15%~+15%. During wheat growth stages,LAI under TS,NT,NTS,TP,and NTP were higher than under conventional tillage and it was obvious that LAI were increased under NTP.