In order to obtain point spread functions(PSFs) of a simple optical system accurately and improve the restored image quality, we present a wide-spectrum PSF estimation method based on PSF measurements. First, narrow-band PSFs are measured, and combining image matching algorithm, the sensor position and the deviation of the optical axis in the real optical system are calibrated. Then, the PSF of each wavelength and field of view is simulated and used for calculating the wide-spectrum PSFs of the real optical system according to the object reflectance spectrum and the spectral sensitivity information of the sensor. Experimental results indicate that the proposed PSF estimation method is better than the narrow-band PSF estimation and blind PSF estimation. The restored image is more stable and its quality is improved significantly. The proposed method can estimate the PSFs of the real optical imaging system accurately.