Abstract: Compared to the traditional spectrometers, the miniature spectrometer is poor in noise and photometric performance. These problems limit its application in the detection of weak light signals. The noise sources of miniature spectrometers were analyzed and different kinds of techniques used for decreasing the noise were introduced. To enhance the capabilities of a selfdeveloped miniature spectrometer, the semiconductor cooling technology was used to decrease the noise. Based on the size of CCD, the structure of refrigerator was designed to improve the cooling efficiency. The noise sources of linear CCD were analyzed and the dark current at different temperatures was tested. The photometric noise and baseline flatness were tested according to the national industry standard. The results show that refrigeration is useful in limiting noise. The photometric noise of the miniature spectrometer is ±0.002Abs, and the baseline flatness is ±0.004Abs.