Integration of the whole mode-locked laser onto a single piece of semiconductor offers a great deal of advantages, including total elimination of optical alignment processes, improved mechanical stability, and the generation of short optical pulses at much higher repetition frequencies. We utilize the semiconductor laser processing technologies to implement the colliding-pulse mode-locking (CPM) scheme, which is known to effectively shorten the pulses and,increase stability, on a miniature monolithic semiconductor cavity. In this paper, we review the principles and recent progress of monolithic colliding-pulse mode-locked quantum-well lasers.