The invention relates to the technical field of laser drive power supplies, in particular to a constant-current drive circuit and method for a laser power supply. The constant-current drive circuit for the laser power supply comprises a main control circuit, a current protection circuit, a power output circuit, a current feedback adjustment circuit, a display circuit, a key circuit, a voltage power supply circuit and an AC-to-DC circuit, wherein the main control circuit is in two-way communication connection with the current protection circuit and the current feedback adjustment circuit separately; and a signal output end of the main control circuit is connected with a signal input end of the display circuit. According to the constant-current drive circuit and method, the damage to a device can be prevented, the output stability and the service life of a semiconductor laser are not affected by abnormal factors in any working environment, an electromagnetic compatibility problem and theconversion efficiency, and the constant-current drive circuit is relatively high in stability and relatively good in reliability.