This paper selects 316LN and Alloy 690, the structural materials with largest contact area with nuclear power plant primary circuit coolant as research objects. Under simulated Pressurized Water Reactor （PWR）primary circuit water chemistry condition, we use static autoclave immersion method and high temperature elec-trocchemistry to study the effect of zinc concentration on corrosion behavior of these two structural materials. The results show that zinc addition can inhibit corrosion rate of materials and corrosion product releasing rate obviously. Compare with Zn-free condition, zinc additioncan make corrosion rate of 316LN and Alloy 690 re-duce by 1.4 times and 1.5 times and reduce corrosion product release rate by 2.3 times at most，respectively. When zinc concentration is 10~50ppb, it can inhibit corrosion rate and corrosion product release rate effectively. When Zn concentration is above 50ppb, Zn concentration doesn’t have obvious effect on corrosion rate and corrosion product release rate.