Photo response non uniformity (PRNU) noise sets a fundamental limit on image sensor performance, especially under low illumination in remote sensing system. After introducing a complete noise model of time delay and integration charge coupled device (TDICCD), a complete model of TDICCD noise is proposed. Then PRNU noise model for all selectable integration stage is developed, which is linearly related to illumination. Moreover, exposure stages are taken into consideration due to their inherent averaging effect, and relationship between nonuniformity parameter and integration stage is developed. Finally a techinque to identify and measure the PRNU noise in TDICCD is presented by analysis of the output images, and the experimental results are illustrated from test system, measured PRNU noise at different illumination and integration stages are also analyzed.