In this paper, a novel aluminizing pretreatment method was developed to enable a strong adhesion of Al2O3 layers on the aluminum-free stainless steel substrate for the application of Fischer–Tropsch microreactor. The Co/Re/W/Al2O3 catalyst coated on a microreactor fabricated with 316 L stainless steel was tested for Fischer–Tropsch synthesis and showed a good activity. Ultrasonic vibration test results showed that the average weight loss of the coating on the aluminized substrate was only one-eighth of that on the untreated plate. A high C5 + productivity of 759.2 mg C5 +/gcat h was achieved at 220 °C and 20 atm under a gas hourly space velocity (GHSV) of 21,000 h− 1, and C5 + selectivity increased with decreasing CO conversion rate. Product distribution shifted toward short-chain hydrocarbons and hydrogenated products at high operation temperatures. Catalyst coating thickness was also optimized to inhibit CH4 production and adjust the olefin/paraffin ratio.