Submicron-sheet zinc phosphate (SZP) and conventional zinc phosphate (CZP) were added with 5, 10, 20 and 30 wt.% (mass concentration) into epoxy coatings, then the evolutions of anticorrosion performances were studied. With a same mass concentration, there were differences on the ratios (λ) of pigment volume concentration (PVC) to critical pigment volume concentration (CPVC) for SZP and CZP pigments. Barrier performances of coatings were determined by λ values, continuous dissolution of zinc phosphate and stress in pigment/resins interface. The advantage of submicron-sheet structure, pigment concentration and the lower stress of pigment/resins interface made 10% SZP coating (λ = 0.35) have the excellent protection performance, compared with other coatings. The results showed that the factors such as different pigment structures, pigment concentrations, continuous dissolution of zinc phosphate, different dispersion status of pigments and stress in the pigment/resins interface cooperated with the prolonging immersion to cause different evolutions of defects, which impacted the anticorrosion performances of the coatings.