Majiayao gold deposit is the representative of typical quartz vein type gold deposits, which blongs to low temperature thermal deposit. Salinity of ore-forming fluid is rather low, and vapor phase compositions are majorly composed of H2O and CO2, accompanying with Na+, Ca+, K+ and F-. Components of fluid is similar with meteoric water. Isotopic values of H and O in ore-forming fluid reflect distribution characteristics of meteoric water under different temperature, water and rock values after being changed with Huilongkuang unit of Qixia superunit. It is regarded that ore-forming hydrothermal solution of Majiayao gold deposit is meteoric water hydrothermal solution.