Abstract: A device was designed to simulate indentation of cables which was different from traditional method of using manual indentation slicing testing with low efficiency and accuracy for high-temperature pressure testing of cables. According to pertinent content of pressure test at high temperature cracking resistance stipulated in GB/T 2951.31—2008, the device incorporated STM32F1 as the primary control chip. Ultrasonic sensors for distance measurement were employed to guarantee the precision of tool cutting. Besides, with distance measurement technique of capacitive grating sensors, the depth of cable indentation could be directly assessed during simulated high-temperature pressure test. In the end, by comparing the measurement data with standard and scrutinizing of uncertainty analysis, the system discovered that the obtained data was more authentic compared to the actual situation, which realized the precision of cable testing.