TR-888B high salt spray resistance magnesium alloy coating agent for all kinds of magnesium and magnesium alloy corrosion, coating use. It is suitable for AZ91D, AZ31B, AZ612, AM50, AZ80-T5, Z31-H24, ZM21, ZK60A, HK31, AM30B and other magnesium alloy die-casting, extruded profiles, plates, pipes. It is used for the pretreatment process of magnesium alloy fittings, such as mobile phone shell, computer bracket, steering wheel and cylinder, and the final process of anticorrosion treatment (neutral salt spray testing can reach more than 120 hours). Coating layer of fine crystalline, neat, film thickness up to 1-8µm; the film weight can reach at least 5-10.5g/㎡; the pores of the membrane can be controlled in 0.2-0.6%. The workpiece by coating the surface of the substrate, and the adhesion of the paint is greatly enhanced, thereby reducing the requirements on the selection of paint. The coating agent has the excellent performance in the counterparts of similar products.