Abstract: Based on ionospheric and tropospheric delay calculated through a GPS reference station network,ordinary Kriging interpolation with Exponential and Gaussian functional model was investigated to estimate epoch-by-epoch ionospheric and tropospheric delay respectively for network-RTK user station.A GPS reference network including six stations(baselines range from 38.8 km to 132.7 km) was used to test Kriging interpolation method.Experimental results show that approximate 2 cm and 5 cm interpolation accuracy respectively for ionospheric and tropospheric delay for a baseline of 79.1 km is achieved using ordinary Kriging interpolation,which indicates that ordinary Kriging(Exponential and Gaussian functional model) is suitable for atmospheric delay interpolation of user station in medium-and long-range network-RTK system.