Based on the data from three wind profile radars, the rain and snow weather process in the central part of Shandong Province from February 12 to 13, 2016 was analyzed. The results are as follows: (1) This rain and snow weather was the return-flow precipitation mainly caused by the combination of low-altitude vortex and surface cyclone. Heavy precipitation occurred in the cold and north side of the cyclone center. The temperature on 925 hPa and near-surface  dropping below 0 ℃ was the important indicator of the conversion from rainfall to snowfall. (2) The change of wind field below 1 km was the signal of precipitation start. The change of strength of low-layer cold pad determined the transition of precipitation phase. The maximum detection height of the radar during snowfall was significantly lower than that during rainfall. The low-altitude wind-shear index would increase significantly at the beginning and end of precipitation. The small increase of the low-altitude wind-shear index during the continuous rainfall period corresponded to the increase of rainfall intensity. (3) The vertical velocity of the wind profile radar could not only reflect the change of precipitation intensity, but also reflect the change of precipitation phase. The vertical velocity near ground gradually decreased during phase transition. (4) Both structure constant of atmospheric reflective index and signal-to-noise ratio showed a decreasing trend with height, and the changes of them could reflect the change of precipitation intensity. They all had zero-level bright band characteristics, and the disappearance of bright band corresponded to the beginning of snowfall.