Abstract: How to revise the drawdown in collecting well to eliminate the effect of pipe loss during calculating yields of radial pipe? That is a problem not to be ignored in forecasting the yields of radial well.The shortcoming in currently available formulas for calculating the pipe loss of radial pipe is analysed in detail. After going through a number of simulant experiments and statistical process, a more effective formula is obtaiend. It reflects the important hydrodynamic feature of inhomogeneous collecting water along radial pipe. Therefore it possesses more satisfiable precision than any currently available formulas.