Abstract: A measurement system for the high voltage pulse power supply on HL-2A has been developed. It adopts the voltage divider based on high-frequency inductance-free glaze film resistor along with the fiber isolation technology based on voltage-frequency conversion. Moreover, a DSP chip is used in the fiber transmission, to realize A/D conversion, simplifying the circuit, enhancing the data transmission speed and anti-jamming ability of the system. The system has been applied to long-pulse(5 s) discharge experiments on HL-2A. The experimental results show that, the system realizes the potential isolation for power supply, and the measured voltage waveforms reflect the supply output faithfully, providing real-time voltage data for the feedback and protection system of the supply.