Given the multiple design variables and cost factors, the cable layout optimization problem for large offshore wind farms is an issue of high complexity. This paper proposes a method for optimizing cable layout based on an improved sparrow search algorithm (ISSA). First, the life cycle cost of the cable is taken as the objective function, constraints are presented considering actual engineering requirements, and the optimization model of the cable layout is established. Then, combining the chicken swarm optimization algorithm and the Prim algorithm, the ISSA is proposed to simultaneously optimize the cable connection topology, cable type and substation location of the offshore wind farm. Finally, case studies are carried out to verify the feasibility of the model and the effectiveness of the improved algorithm. The results show that the life cycle model provides a comprehensive assessment of the economics of the cable layout. Compared with the original algorithm, the ISSA has greater ability to find the optimal solution. In addition, compared with the improved algorithms in the literature, the ISSA has a simple structure, high efficiency and strong optimization stability. It is suitable for the optimization of cable layout for offshore wind farms. This work is supported by the Natural Science Foundation of Hunan Province (No. 2021JJ30875).