Abstract: Due to complexity, variability and specificity of tunnel through a karst area, added by regional differences and the uncertainty of the hydrological cycle, all kinds of forecasting methods have their own shortcomings, resulting in some difference between the forecasted water inflow and the actual water inflow.The paper, by combining the differences and characteristics of rapid and slow water recharge in karst area and from the hydrogeological mechanism and characteristics of karst water movement, used three methods, i.e, water balance method, groundwater runoff modulus method and Expert's Judging System to predict and analyze karst water bursting in Jinkuidi extra-long tunnel.The water volume calculated by wtater balance method was the biggest, that calculated by runoff modulus was the smallest, and that given by the expert system was medium.Multual verification proved that the expert judging system was the most precise, the method emphasizes the effect of precipitation on karst water bursting in tunnel and increases the precision of karst water inflow prediction in tunnel.