A remote IO card based on RS485 bus is designed for the measurement system used in anti-radiation experiment(transient dose rate, the total dose rate etc.), which consists of USB to RS485 interface module and RS485 to IO control module. The FT232 and isolating type RS485 driver are utilized for conversion from USB to RS485; the 32 bit MCU STM32 and isolating type driver are adopted to control remote IO. As an important part of the whole measurement system for anti-radiation experiment, the IO card is adopted to finish the transient dose rate experiments, the total dose rate and the neutron experiment, and the data is obtained. According to a series of experiments, the IO card is proved to be of low requirements of field wiring, high reliability and satisfying the actual application.