A photolithographic model for optical disc mastering is established.In this model,vector diffraction is used to calculate the intensity distribution of focused light spot,and the light propagation in multi-layer film structure is used to describe the light propagation in photo-resist.The experimental and simulation results are presented,including the influences of key process parameters on typical multi-level pit width and depth.These process parameters consist of photo-resist thickness,development time and developer concentration.Experimental results show that the decrease of photo-resist thickness will cause the increase of width and the decrease of depth.The increases of development time and developer concentration have the same effect,both will cause the increases of width and depth.The deviation between simulation and experiment is kept within ±5 nm,which shows that the experiment is coincident with the simulation well.The analysis results are helpful to practical multi-level disc mastering.Meanwhile,the model can be used to analyze other process parameters and other disc formats.