The catamaran bait boat is one of the feasible schemes to realize bait sprinkling in the crab pond. In the presence of water plants in the channel, in order to reduce the cruise resistance and improve the endurance of the bait boat, two new bottom profiles, sharp bottom and round bottom, were designed in this paper. Based on the Reynolds average N-S equation, the dynamic calculation models of the boat under different draughts and speeds are constructed. Taking the flat bottom boat as the contrast boat, the CFD numerical calculation and the sink test resistance are compared and analyzed,and the data error is less than 9.6%, which shows the effectiveness of the calculation model. The results show that:the round bottom boat has better resistance reduction effect at the speed of 0.50-2.00 m/s, and the resistance reduction rate is 3.92%-16.27% compared with the flat bottom boat; the round bottom boat can reduce the sliding friction resistance between bottom and water plants; the economy of bait boat is at the speed of less than 1.50 m/s and the draft is less than 0.18 m. The further test results of the round bottom boat show the effectiveness of the proposed optimization scheme.