GaN-based semiconductor lasers have great application prospects in fields such as laser display, laser lighting, visible light communication, atomic clocks, medical instruments, and have been widely studied. So far, most GaN-based lasers are grown on expensive 2-inch GaN native substrates, resulting in a high device cost. Compared to GaN substrates, silicon substrates have higher quality, larger size and lower cost together with automated process lines, and can significantly reduce device costs. Therefore, GaN-based lasers grown on silicon have received widespread attention. This chapter first introduced the growth and characterization of GaN-based laser materials grown on silicon, then elucidate the device fabrication and characterization of GaN-based laser diodes grown on silicon. Finally, the content of this chapter was summarized.