The invention discloses an area array high dynamic range noctilucent imaging satellite in-orbit relative radiation calibration method, which comprises the following steps: in-orbit dark current calibration and correction: obtaining dark current parameters of a noctilucent sensor under different imaging parameters; calibrating and correcting the low-gain image of the noctilucent sensor in the daytime to obtain a relative calibration coefficient of the image of the noctilucent sensor under the low-gain imaging parameters in the daytime; and constructing a daytime-night radiation reference transfer model, so that correction of a high-gain image at night by a relative calibration coefficient under daytime low-gain imaging is realized. The method is suitable for in-orbit relative radiation calibration of the area array noctilucent satellite, and has the advantages of being high in precision, more convenient to use and low in cost.