The invention discloses an efficiency optimization system of a single-segment linear LED drive circuit. A current control circuit is arranged to control the shape of flowing through LED current, the output of the current control circuit is used as a the positive end of a control voltage connection error amplifier EA, the input end of the current control circuit is connected with the negative terminal voltage VA of an LED lamp string, and the shape of the flowing through LED current is a combination of a flat current and a concave current through the current control circuit; when the voltage ofan input bus is reduced, the flowing through LED current is the flat current, and the flowing through LED current is the concave current near the voltage peak value of the input bus; the flat currentis used for cutting off the concave current near LED on and off points to form a top cutting shape current; and the optimization of the efficiency of a single-segment linear LED drive power supply isrealized, and meanwhile, the optimization of the current overshoot or stroboscopic problem is further realized.