Abstract: With the rapid development of laser technology, laser sources have been widely applied in the measurement of spectral radiation and optical properties. Compared with the traditional light sources, laser sources have the advantages of high power, wide spectrum and extremely low wavelength uncertainty. A set of photodetector response calibration device based on the wide-band tunable laser light source was established, in which the spectral coverage of the laser light source was 190 nm~4 000 nm, the laser pulse width was about 130 fs, and the repetition frequency was about 80 MHz. In order to avoid the impact of high peak power pulsed light on the calibration of the detector, and improve the linearity of the measurement, a converter of converting pulsed light to continuous light was successfully developed by using the inherent characteristics of the optical fiber. At the same time, a set of laser collimation and beam expansion optical paths was built based on the laser source, and a monochromatic uniform radiation field with an inhomogeneity of 0.29% was obtained at a wavelength of λ=550 nm. The monochromatic uniform radiation field plays an important role in the application of high-precision detector calibration, and the calibration measuring device based on it has a positive significance in the field of metrology.