Ultrashort-pulse lasers are attractive sources for a number of applications including optical fiber communication and biomedical imaging etc. Semiconductor mode-locked lasers are excellent candidates for ultrashort pulse generation due to their advantages in compactness, weight, energy efficiency and cost. We give a comprehensive introduction to the latest progress of semiconductor mode-locked lasers based on an overall review of recent research reports for the semiconductor mode-locked lasers operating at the wavelength range from 400 nm to 2 μm.