In the use of image sensors such as CCD, CMOS and so on, the noise caused by thermal dark signal will influence the imaging results to a certain extent. Dark current noise exists in every photoelectric devices and it is directly related to the temperature. So it’s a principle way that cool the image sensors’ temperature to suppress the dark current noise. This article presents a kind of TEC cooling package integrated with four stages TEC, a heat sink and an insulating cavity, to meet the requirement of image sensors’ refrigeration. Theoretical analysis of this cooling package was done from the view of heat transfer. The modeling and thermal simulated analysis are performed by finite element simulation analysis software ANSYS Icepak, comparing the experimental results in the conditions of different ambient temperature, different heat load and vacuumizing or filling the cavity.