The InGaAsP/InP multiple-quantum-well coupled-circular micro-cavity laser with a radius of 15 μm is measured by the constant current aging test at 100 mA for 1400 h. The variations of laser output power and threshold current during the test are consistent with those of a semiconductor laser under the gradual degradation mode except for three abnormal variations caused by the change of mode or ambient temperature, that is, the lifetime of the laser can be evaluated according to the output power variation. The laser output power is reduced by 50% after 1200 h, that is, the lifetime of the laser is about 1200 h at 100 mA.