A new method is proposed to design coding gray-tone masks based on modifying position and shape of cell on mask. Pre-distortion applied to modify mask has been implemented by introducing this method according to the nonlinear effects in aerial image and resist development. Based on the theory of partial coherent light imaging and the resist development model, the intensity distribution through the coding gray-tone mask and exposure of photoresist have been simulated. The coding gray-tone mask was fabricated by e-beam exposure system and microlens array with continuous relief distribution on photo resist was obtained.