Ptychography is a coherent diffraction imaging technique and has rapidly developed over the last decade, becoming an indispensable imaging tool in most X-ray synchrotrons and national laboratories globally. In the visible light regime, optical ptychography can be divided into two: lens-based Fourier ptychography and lensless-based coded ptychography (CP). CP is a novel lensless on-chip microscopy imaging technique, and its advantages include a large field-of-view, high-resolution, aberration-free, label-free, field portability, and slow-varying phase imaging. In this review, we discuss the basic principles of CP and summarize its recent progress. Additionally, we analyze its imaging performance and highlight its biomedical applications. Finally, we conclude this review article by pointing out several directions for its future development.