In order to meet laboratory radiometric calibration requirements for increasing optical aperture of optical remote sensors, a kind of high-light-level integrating sphere calibration source is designed based on near small source method. Meanwhile the optical and structural parameters of the high-light-level integrating sphere calibration source are designed in detail. To solve the problem of heat dissipation of high-light-level integrating sphere calibration source, circulating cooling water is used as cooling means, and special cooling pipes are designed. The high-light-level integrating sphere calibration source is analyzed by finite element analysis method of thermal simulation in the state of 0.1 m/s of the circulating water. From the analysis results, the temperature around the tungsten bromine lamp is about 125 ℃ , the outlet temperature of the high-lightlevel integrating sphere calibration source is about 80 ℃ . From the experimental results, the temperature around the tungsten bromine lamp is about 125 ℃ , the outlet temperature of the high-light-level integrating sphere calibration source is about 100 ℃ . Through the comparative outlet temperature difference of the highlight-level integrating sphere calibration source, the causes are explained, and the validate of simulation analysis and theoretical calculations are verified. Meanwhile it can be suggested in the measurement data that the integrated spectral radiance of the high-light-level integrating sphere calibration source is 6714 W/(m2﹒sr) in the range of 400 nm to 900 nm.