A modified extended-ptychographical-iterative-engine (ePIE) algorithm is proposed to overcome the disadvantages of ePIE technique and reduce the influence of stage hysteresis or backlash error. The exit wave of a rotatable "screen" illuminated by plane wave is used as the illumination on the specimen, and the complex transmission functions of the rotatable object and specimen can be simultaneously reconstructed. Compared with the standard x-y scanning PIE algorithm, the proposed algorithm can completely avoid the influence of stage hysteresis (or backlash error). The proposed algorithm also has higher convergence speed and better accuracy than the standard PIE algorithm.