Aiming at the shortage of modern liquid crystal instrument development technology, an electric vehicle instrumentation system based on ARM is developed. The system adopts modular design that including signal acquisition, signal processing and data display. The hierarchical software structure is adopted to adjust the operation order based on the priority scheduling, which makes the logic simple and easy, and improves the reliability of the system. In the design of hardware circuit, the system takes various anti-interference measures to enhance the electromagnetic compatibility. The experimental results show that the system can display the parameters of electric vehicle accurately and meet the requirements.