Differential amplifiers play an important role in the analog circuit design because of their excellent performance as input amplifiers and the straightforward application with the possibility of feedback to the input. The differential amplifier circuit characterized in terms of self-bias capability, common-mode rejection, voltage gain, and the gain-bandwidth product. In this paper a new model for high performance low voltage CMOS differential amplifier has been proposed. This model is simulated using SPICE simulator and optimized device parameter with .25 micron CMOS technology.