The hydrodynamic performance of catamaran has a vital influence on its sailing speed and endurance, so it is of great significance to study the hydrodynamic performance of catamaran. Based on STAR-CCM+ numerical simulation software, the method is verified by grid independence and time step independence, and the accuracy of the numerical calculation results is proved. Then, the hydrodynamic performance is analyzed by numerical calculation of different conditions such as different sheet spacing, sheet shape and oblique navigation Angle. The calculation results show that the resistance of catamaran under the condition of k/L=0.2 and Fr=0.4 has a sudden rise compared with other conditions with the same speed, and the total resistance coefficient reaches the maximum value of 14.56*10-3. When the plate is rotated 2° in vitro, the resistance value is the smallest compared with other rotation angles.It is found that the total drag coefficient of the catamaran increases first and then decreases when the catamaran is sailing straight or oblique, which indicates that the catamaran has certain superiority when sailing at high speed.