A new absolute method of radiance calibration was introduced,including the principle and its experimental setup. An ultraviolet laser (355 nm) was used to pump the nonlinear crystal BBO (β-BaB2O4),producing two correlated-photons whose wavelengths were 532.75 nm and 1064 nm,respectively. The under-calibrated laser was injected along the propagation of the infrared down-converted photons. With the high correlativity of the two VIS-IR correlated photons,through the measurement of the visible down-converted photons,the radiance of the injected laser source can be calculated,allowing the radiance of an infrared source can be measured with the high-quality visible detectors. The measurement result shows good linearity at different power of injected laser. At last,based on the estimate of the efficiency factor of the system,the radiance at a fixed power of 3.39 mW was calibrated,with the result 4.09×1017 W/(m2·sr) and its relative uncertainty 4.78%.