In order to raise safe and technical management level in oil and gas stations and depots, designed is a set of programmed flammable gas centralized safety monitoring system according to concentration distribution of flammable gas in oil and gas stations and depots. Distributed modules are adopted in the system and RS-485 field bus is used to connect each module. Used is configuration software as center monitoring development software, adopted is flammable gas alarm of self-developed simulation ADAM 4017 module communication protocol for flammable gas detection and applied is ADAM 4052 digital input module for manual tour-inspection, which can realize remote communication between center host computer and modules. The system has such function as real-time treatment of flammable gas concentration at each test point in oil and gas stations and depots and autoarchivering and network transmission of manual tour­ inspection information. If flammable gas concentration exceeds relative limit, location icons will flash and send voice alarm signals so as to dispose oil and gas leakage in time and prevent any accident.