In the thesis, we first present the actual design for digital camera including both fixed lens and zoom lens. Then we discuss how to set the first order data according to the sensor. Finally we discuss how to appraise the quality of Image. In the system of fixed lens, we design actually the digital camera for the sensors of two million and four million pixels. In the system of zoom lens, we design actually the digital camera for the sensor of three hundred thousand pixels. Then, based on the data, we design actually the digital camera for the sensor of one million and three hundred thousand pixels. The zoom ratio of 2 is achieved.