In this paper, Laser Doppler Velocimetry (LDV) is applied to taxi meter checking through the Doppler effect, and the system design is completed by using a double oblique radiation asymmetric structure laser velocimeter, bispectral peaks signal processing technology, portable external tooling and a well-interacted operating system. Theoretical analyses and experiments demonstrate that the LDV-based taxi meter calibration system performs effectively. The pneumatic attachment of the apparatus enhances portability, allowing for broader application scenarios. The innovative dual oblique, asymmetric optical path design minimizes the impact of road irregularities on measurement accuracy, thus enhancing the system's reliability and precision. The dual spectral peak signal processing technology improves the speed of signal processing, enabling real-time processing of velocity signals. The system also features a custom-designed user interface, which is simple, user-friendly, and has a high error tolerance, greatly simplifying the meter calibration process. Consequently, the LDV-based taxi meter calibration system can meet the real-world demands of the market and solve prevalent challenges in meter calibration, providing substantial practical value.