The invention relates to a simulation test device for detecting deck steel corrosion resistance on oil cargo tank and a use method of simulation test device. The test device comprises a reaction kettle, and an outer tank body (5) for containing the reaction kettle, wherein the reaction kettle comprises a kettle body (14) and a kettle cover (13), a gas source (1) is orderly connected with a gas flow controller (3) and a gas mixer (4) through a gas circuit (2), a gas inlet interface is connected with the kettle cover (13); a gas outlet interface of the kettle cover (13) is connected with a tail gas processor (18); an outer tank body temperature measuring probe (7) is arranged in the outer tank body (5), an outer tank body temperature control element (6) is arranged at the top of the outer tank body (5); a temperature control water circulator (16) is communicated with the kettle cover (13) through a water pipe (15); a kettle bottom temperature control element (10) is arranged at the bottom of the kettle body (14); a distilled water temperature measurement probe (9) is arranged in the distilled water in the kettle body (14); a sample temperature measurement probe (8) and a sample temperature regulating plate are arranged in a sample installing groove (12). The device disclosed by the invention is simple and convenient to operate, precise in control, stable in operation, and the experiment environment well accords with actual service condition.