Node water demand and water loss coefficient water supply pipe network possesses obvious uncertain. In order to analyze the influence of node water demand and uncertainty of water loss coefficient on hydraulic characteristics of water supply pipe network,the paper assumed that their random change obey the normal distribution condition of their normal distribution condition,and took Monte Carlo sampling method to get the values of node water demand and water loss coefficient.It applied steady-state hydraulic model to calculate corresponding water head of node pressure tube and pipe flow.At last the paper proposed the calculation method of statistical value of node pressure tube water head and pipe flow which is applied in two pipe network system.