The invention relates to a ramp-error compensation circuit for a peak current controlled BUCK converter, belongs to the technical field of switching power supplies and solves the problem that the output current of the peak current control BUCK converter has a static error after ramp compensation in the prior art. The ramp-error compensation circuit disclosed by the present invention comprises a ramp compensation sub-circuit, an error compensation sub-circuit and a conditioning amplifier sub-circuit, wherein the error compensation sub-circuit comprises a ramp compensation sub-circuit, an errorcompensation sub-circuit and a conditioning amplifier sub-circuit. The input signal of the error compensation sub-circuit is taken from the output voltage of the BUCK converter, and the error compensation value is proportional to the output voltage of the BUCK converter and equal to the static error of the output current of the ramp compensation sub-circuit. Therefore, the BUCK converter with anyduty cycle can achieve error compensation and eliminate the static error caused by ramp compensation.