The invention discloses waterborne two-component 
varnish and a preparation method thereof. The waterborne two-component 
varnish is formed by mixing a component A and a component B in the 
mass ratio of(2.5-3.5):1, wherein the component A comprises, by weight, 25-40 parts of waterborne 
acrylic resin, 25-40 parts of waterborne 
polyester resin, 0.1-1 part of base material 
wetting agent, 0.1-1 part offlatting agent, 0.1-1 part of defoaming agent, 0.1-1 part of 
ultraviolet absorbent, 0.1-1 part of bactericide, 5-10 parts of cosolvent, 0.1-1 part of 
thickening agent and 2-5 parts of 
carboxymethyl chitosan; the component B comprises, by weight, 40-60 parts of 
isocyanate curing agent, 0.1-1 part of adhesion 
promoter and 40-60 parts of cosolvent. The fullness, glossiness, flatting property, construction performance and mechanical properties of the 
varnish can reach the standards of high-performance oily varnish and are higher than those of existing waterborne varnish, and the varnish has the 
advantage of being low in content of VOCs.