In order to investigate the effect of Si addition in zirconium alloy,two kinds of alloy with and without Si are prepared by a sequence of three vacuum arc re-melting.Optical metallograph,TEM,corrosion tests and XPS are carried out on these samples.It has been discovered Si has an effect on heterogeneous nucleation and decreases recrystallization rate.Besides hexagonal precipitates Zr（Nb,Fe）₂,body-centered tetragonal SiZr2 is also found in Si-containing alloy.Si-containing alloy also exhibits better waterside corrosion resistance than that of the other alloy.From XPS analysis,Si presents two electronic states in alloy.The valence of Si tends to be-4 in Zr-Si chemical bond.In terms of Wagner-Hauffe’s theory,Si^4- might produce cation vacancies in the oxide and limit the access of O^2- to them for keeping local electric neutrality.Large amount of electrons are provided to neutralize anion vacancies when Si^4- turns to Si⁴⁺.For this reason,better corrosion resistance is exhibited.