The biggest advantage of a CMOS area array sensor is that it is less expensive than a CCD sensor. A miniature spectrometer use an area array CMOS sensor MT9M001C12STM as detector was developed. The prototype uses an asymmetric cross Czerny-Turner optical structure. Its photometric accuracy and linearity were investigated, and the photometric deviation arise from stray light was analyzed. The elementary performance was tested as follows: wavelength range 380~800 nm, the integration time can be selected from 1 ms to 500 ms according to the light intensity, spectral bandwidth 6 nm , wavelength accuracy ±1 nm, photometric accuracy ±0.03 AU. Results showed that after calibration and nonlinear correction, this CMOS spectrometer is capable for routine fast analysis.