The electronic endoscope can only observe the front field of view. In order to eliminate patients′ injury from the blind area in the rear, an electronic endoscope which can observe both the front and rear field of view at the same time is designed. The first lens is designed according to the method similar to double agglutination. Circular reflective film is added to the front surface of the lens to meet the need of transmission and reflection. The endoscope chooses spherical design to reduce the cost. The system is optimized by Zemax stimulation, and equipped with 1/10 in (1 in=2.54 cm) charge coupled device (CCD) to receive image. The results show that the radial dimension of the system is 5.5 mm, which meets the requirement of small size. It also has uniform illumination at image plane on axis and off-axis. The modulation transfer function (MTF) value of this system is greater than 0.75 at the spatial frequency of 100 lp/mm at the whole view, which is close to the diffraction limit and meets the resolution requirement.