Abstract: Measurement speed and measurement accuracy are two important indicators of the phase laser ranging system. Aiming to the needs of high-speed and high-precision ranging system, a high-speed digital phase detection method based on the Vector Inner Product (VIP) method was studied. The phase detection performance of the VIP method was simulated and tested in terms of the number of phase detection calculation points, phase detection calculation speed, and phase detection accuracy. The simulation and experimental results were compared with the traditional digital frequency domain phase detection method (Discrete Fourier Transform (DFT) method), which show that the VIP method has higher phase detection speed and phase detection accuracy. When the signal modulation frequency is set as 50 MHz, based on high-speed sampling board, the measured phase detection accuracy is better than 0.1°, the ranging accuracy is within 0.2 mm, the phase detection processing speed of the VIP method is 3 times faster than that of the DFT method under the circumstance with the same number of calculation points. Referring to the high phase detection accuracy and fast phase detection speed, all the analysis data show that the VIP method has the significant advantages, which is suitable for the high-speed and high-precision laser ranging systems.