The study on the improvement of resistance performance is very important for coastal fishing boats in Korea, because the prices of fuel oil are gradually risen and the demand of high-speed fishing boats is increased lately. This study is concerned with the improvement of the resistance performance for Korean high-speed small coastal fishing boats. A semi-planing hull form of Korean small coastal fishing boat is selected in the role of initial hull. From the modification of the hull form parameters and the local characteristics of the hull form, the improvement of the resistance performance is achieved. The resistance performances of the initial and the modified hull forms are estimated by using a numerical simulation method. Also, ship model tests are carried out in ship model basin.