Abstract: Water column produced by near water surface explosion is an important topic of study and simulations based on its theory and experiment has great significance. An effective method to solve such problems is suggested. Program MSC.DYTRAN and program PAM-FLOW were introduced in the calculation for 2m underwater explosion with 2kg of TNT. They deal with the problem about shock wave impacting the interface of the liquid and air. The result fits the theory and the experiment well. Underwater explosion of TNT calculated by these programs was finally analysed. The results proved to be consistent with those calculated by similar explosions.