As a new material,magnesium alloy has the advantage that other metal materials cannot be compared.The magnesium alloy is mainly composed of magnesium.Because magnesium is relatively active and there are a lot of gaps on the surface of magnesium alloy,it is easy to be corroded by the environment.Therefore,a set of closed varnish and protective primer have been developed on the basis of chemical oxidation film formation.The resin for sealing varnish and protective primer is made of modified epoxy resin and composite polyamide curing agent.The pigment and filler of the protective primer is made of passivation pigment zinc chrome yellow and shielding filler mica powder,graphene,etc.,so that the magnesium alloy substrate can be sprayed with a coating to resist neutral salt spray and heat and humidity up to 1500 h.It is fully capable of achieving the corrosion protection required for our use of magnesium alloy substrate.