Catamarans have wider deck area and larger transverse stability compared to monohull ships. For fishing vessels, since these features are great advantages, catamaran hull form is a promising. Most of problems in the design of the catamaran are related to the seakeeping performance. Therefore, it is necessary to examine the seakeeping performance by the numerical calculation in the design of fishing catamarans. In this report, the calculation methods based on a strip method and results of seakeeping performance of fishing catamaran are presented. In addition, the outline of a constructed fishing catamaran is also described and problems and future tasks are addressed.