In the process of building a maritime power, the study of fish morphological characteristics and fish swimming drag reduction mechanism is crucial to the design and complex swimming behaviour of bionic robotic fish. In this study, taking Dasidicus gigas as the research object, through the visual image acquisition of the samples of the fish, the external contour equations and 3D simplified model of the fish body were established based on the length of the biological characteristics. The analysis shows that the curve fitting method reduces the measurement error caused by the relaxation and deformation of the muscles in different body parts; the analysis shows that the simplified model of bionic squid based on contour equation has lower travel resistance when swimming at high speed, and the drag force coefficient is between 0.000 4 and 0.001 1 at a speed of 13.89 m/s, and the importance of morphology in the mechanism of drag reduction is revealed; this posture of the squid at high speed provides a fluid morphological basis for the squid The biomorphic external profile and CFD methods provide reference for further design and research of the biomimetic squid.