High-speed railway embankment as the supporting body of the train and track is directly exposed to the complex climate conditions such as the rainfall, evaporation and other environmental events. These conditions change the water content, suction and shear strength of the filling soil, and further affect the stability of the embankment. A moisture migration model of the high-speed railway embankment with considering environmental effects is proposed. The model is verified by comparing with the measured data of a highway embankment in Rouen, France. Based on the meteorological data of Beijing and Shanghai in 2013, the volumetric water content (VWC) response of the high-speed railway embankment is calculated to investigate effects of climate conditions and soil types. The result shows that, the soil type and climate condition significantly affect the moisture variation of high-speed railway embankment. The influential depth of atmospheric environment on the VWC of sandy embankment is small, but the shallow embankment is affected by the atmospheric environment significantly with a large amplitude of VWC fluctuation. The influential depths of atmospheric environment on the VWC of silty and clayey embankment are relatively deep, but the amplitude of VWC fluctuation is small at every depth. The VWC of embankment under weather condition of Beijing has a huge seasonal variation and the VWC of embankment under weather condition of Shanghai fluctuates significantly with each rainfall.