This paper presents the results of hull form design and powering performance for a 2.500 ton class trimaran frigate. A series of resistance tests and numerical calculations have been conducted to figure out the influences of side-hull form and position on the resistance characteristics of the trimaran. And the propulsion test was conducted to investigate the propulsion efficiency of the trimaran, and the powering performance of the trimaran was compared with that of the similar mono-hull ships in full scale. From the research it was found that the longitudinal position of side-hull had a large influence on the resistance characteristics of the trimaran while the side-hull form and transverse position had a small influence on it. The trimaran showed favorable resistance performance when the side-hull was located near the stern of trimaran, which was resulted from the fact that the side-hull stem was located near the primary wave hollow generated by the main hul1. The powering performance of the trimaran was superior to that of the similar mono-hull ships above the middle speed range.