In this work, a high-speed trimaran model of a scale of 1:100 was experimented in a circulating water channel. There are three control factors were investigated in this paper, that is, transverse span, longitudinal position and draft, and one noise factor-ship speed, which were used to conduct the parameter design in this work. The result shows that, on the condition of low speed, a trimaran can not offer better drag characteristic than a traditional mono hull ship, due to the fact that the area under water for trimaran is large. Better drag characteristic can be achieved for a trimaran only as Froude Number is greater than 0.2.