A novel photoelectric device-photo-BJMOSFET (Bipolar Junction Metal-Oxide-Semiconductor Field Effect Transistor) fabricated on SOI film was proposed in this paper. The photo-BJMOSFET operates in the depletion but not inversion region to decrease dark current. Due to two kinds of carriers (electron and hole) in this device, it is more sensitive than the conventional MOS structure under the same operating conditions and structure parameters. Numerical calculation of the analytical model indicates that photo-BJMOSFET has high sensitivity and SNR (Signal to Noise Ratio). In addition, it can eliminate the high dark current of PN junction under CMOS process, and promise compatibility with CMOS process.