Abstract: In view of problem that performance of RS485 bus will be decreased by underground complex electromagnetic environment, so as to influence data transmission of coal mine safety monitoring and control system, the paper indicated that it should make anti-interference design of RS485 bus through aspects of fault insurance circuit, electrical isolation, interface protection of anti-surge over-voltage and communication software programming, and gave implementation of the anti-interference design. The actual application showed that the anti-interference design can ensure stable running of data transmission of coal mine safety monitoring and control system.