Abstract: Objectives The purpose of this research is to design the original bilge keel of 66m ocean-going squid fishing, and optimize the bilge keel design scheme that can improve the wave resistance and ensure the rapidity of the fishing boat, so as to provide a reference for the selection of bilge keel for Ocean-going squid fishing. Methods By converting the length and width of bilge keels, five different sizes of bilge keels are designed. Based on the CFD method, the VOF model and the overlap grid technology are used to numerically simulate the free roll attenuation of these six different bilge keels of ocean-going squid fishing, and reliable resistance values and free roll attenuation time curve are obtained. The effects of bilge keel length, width and length-to-width ratio on rolling motion were studied. Through the comparison of roll motion, three optimization schemes with better roll reduction effect are selected, and the resistance numerical simulation is carried out to study the optimization design scheme of fishing boat. Results The simulation results show that compared with Model#0, the roll damping of Model#3 increases by 23.37% when Fr=0; the roll damping increases by 25.31% when Fr=0.168; the roll damping increases by 85.80% when Fr=0.230, and the roll damping effect is better. Moreover, among the three bilges keels with good roll damping effect, Compared with Model#0, Model#3 has the smallest resistance increase value, which can meet the requirements of fishing boat rapidity on the basis of obtaining good wave resistance, Conclusions The research results can provide a useful reference for improving the wave resistance and the selection of bilge keel of ocean-going squid fishing.