Analysis Nudging in different resolution domains was adopted for dynamic downscaling, and the result of two typical months of July and October, 2015, which represented summer and autumn, was evaluated in Liaoning Province of China. Results showed that significant improvement was present in large-scale background with AN in WRF, such as geopotential height at 500 hPa and relative humidity at 925 hPa. According to the characteristics of error between simulated and observation of surface variables, including temperature and relative humidity at 2 m, wind speed at 10 m and precipitation, it also showed that analysis nudging at 12 km and 4 km resolution was more effective than at 36 km. However, after using analysis nudging at 4 km, there was no improvement of the precision of surface variables anymore, and the surface temperature and precipitation were even worse than using nudging at 12 km grid. This suggested that, according to the resolution of background filed, nudging in high resolution grid was ineffective after using analysis nudging at the relatively coarse model grid.