Due to the complexity of the optical path of the laser 3D projection system and the influence of the shape and size of spatial targets, it is difficult to achieve ideal projection effects in a specific space, resulting in a significant deviation between the projection target and the actual projection point. Therefore, a radiometric illumination calibration method is proposed. Using two different shapes of radiation surfaces and sensitive surfaces, rectangular and circular, respectively, to construct radiation irradiance measurement instruments and obtain four different radiation irradiance measurement results; Using the Stefan Boltzmann total radiation law, calibrate the measurement results, and then complete the calibration of the irradiance of intelligent laser 3D projection space targets. The experimental results show that the radiometric calibration results of the proposed method are basically consistent with the actual results, and the radiometric calibration error remains within 6 W·m2.