Active pixel sensor (APS) complementary metal-oxide-semiconductor (CMOS) sensors have performances competitive with charge coupled device (CCD). A number of potential advantages bring it a good prospect of application hyper-spectral imagery area. Several issues about applications of CMOS sensor for imaging spectrometers are discussed. Noise model is built and sensitivity performance of hyper-spectral imagers using CMOS sensors is analyzed. Spectral image calibration method is proposed based on the structure and features of CMOS detectors. Spectral imaging system including electronics and optics is formed, and analyses are proved by imaging experiment. Results show that CMOS sensors can meet the sensitivity requirement of hyper-spectral imagers and are available for hyper-spectral applications.