To guarantee the palmprint image definition satisfying user′s requirements acquired by non-contact palmprint recognition system and shorten recognition testing time, the relation model between palmprint image definition and error recognition rate is established, and the improved non-contact on-line palmprint recognition simulation system is realized. The image definition evaluation function is introduced, and the relation model between image definition and shooting distance is established. The relation model between image definition and error recognition rate is established. The non-contact on-line palmprint recognition simulation system is realized which is based on image definition evaluation module. The experimental results show that the improved simulation system ensures the effectiveness of the image acquisition and reduces the error recognition rate.