By using routine observational, satellites and surface automatic observational data,far distant typhoon and heaviest rainfall process of Shaanxi in 2010 were analyzed. The conclusions are as follows. Low-pressure system between 500 hPa mainland high pressure and subtropical high pressure maintained stably and the short-wave cold troughs at the broad bottom of low-pressure moved continuously to south, and merged into low-pressure system situated between two high-pressure; furthermore, typhoon "Conson" located in the South China Sea for long time and the southerly jet near the center of typhoon extended northwardly and arrived at Shaanxi through the ridge line of the subtropical high over western Pacific, which caused persistent heavy rain in Shaanxi province. The transportation channels of water vapor and enthalpy at 850 hPa between the typhoon and Shaanxi was established and the warmer and wetter atmosphere was carried toward Shaanxi continuously. Heavy rains occurred in the overlapped area of upward motion, which locates in two circulations, and in dense belt line of enthalpy at 850 hPa. Convective instability and conditional symmetric instability are the important mechanism for development and maintenance of heavy rains. When big value area of moist potential vorticity at high level spreads downward, heavy rains become stronger. Heavy rains fall in dense belt of moist static temperature line, and they are slightly biased towards high-energy center side.