The invention discloses a laser signal detection device based on a DSP embedded system and a control method thereof. The laser signal detection device comprises a four-quadrant detector, a detector interface board, a signal processing board, a data processing board, and a power board. The detector interface board includes a single-ended conversion differential circuit. The signal processing board consists of a differential receiving circuit, a main gain control circuit, a variable gain control circuit, a summing circuit, a comparison circuit and a peak holding circuit. The data processing board includes a DSP processor, a D/A conversion circuit, an analog switch circuit, and a CAN bus driver circuit. The CAN bus driver circuit is connected with an upper computer; the D/A conversion circuit is connected with a detector assembly, the comparison circuit and the variable gain control circuit respectively. And the DSP processor is connected with the peak holding circuit, the comparison circuit, the main gain control circuit, and the four-quadrant detector by a GPIO module. With a control algorithm, detection of a fixed-cycle laser signal and target offset angle calculation can be completed.