Based on the principle of eddy current sensor，We use CS16f505 as the main control chip and design a system of digital display vernier caliper. We analyze the function and performance of the caliper on the market, and conclude that the effective measurement length is 150 mm and the measurement resolution is 0.01 mm. Also, the low power consumption design is needed. Then the paper introduces the composition and block diagram of the hardware system, analyzes its basic principle, the resources of CS16F505, and the design of fixed gate and sub board. Next, it focuses on the software design based on MCU, including the overall framework design and the design of each module. Finally, the system is tested after the completion, and a variety of lengths are measured. The caliper scheme can achieve the accuracy of 0.03mm and the resolution of 0.01mm.