The traditional solar street lamp controller is constrained with the low charging efficiency and the low precision of the constant current source. A novel solar street lamp controller based on the multi-channel PWM constant current technology is designed. A composite DC-DC converter is adopted to realize charging and discharging efficiently through controlling multi-channel PWM signals. During the charging stage, the efficiency of charging is improved by tracking the maximum power point with the perturbation and observation method. During the discharging stage, the duty cycle of the relevant PWM signals are used to implement the high precision constant current source for driving the LED street lamp, which can be adjusted automatically through real-time detecting of the lamp’s actual current. The test results show that the charging efficiency of the street lamp controller can be improved evidently, and the charging speed increases 4% to 7%. Furthermore, the precision of the constant current source reaches a high level of 2.5%.