Tropical Cyclones (TCs) have caused severe disasters in various places in Japan. Kochi prefecture has experienced TC disasters various times, and thus, it is important to evaluate impact of future change of TCs on Kagami river basin. In this study, we developed an algorithm to evaluate the impacts of future change of precipitation caused by TCs into discharge. The algorithm classifies TCs into some patterns according to track and intensity of TCs. Then, stochastically simulated TCs are classified into the extracted TC patterns. Subsequently, the functions to generate TC induced precipitation are also estimated for each of TC patterns. Execution of the proposed algorithm to Kagami river basin indicated annual maximum discharge might increase by nearly 30% when we consider 21 % decreasing of central pressure and future change of thermodynamic environment.