The grid-connected island microgrid is interconnected with the main grid through a tie line. How to reasonably use the energy storage system and tie line is the key to the optimal interaction between the island microgrid and the main grid. This paper proposes an optimal operation strategy of an island microgrid that comprehensively considers tie-line asset utilization and energy storage life characteristics. Random chance constraints are used to describe the uncertainty of natural resources and loads, and battery throughput life models are used to describe charging and discharging and the impact of the state of charge on the life of the battery. In the case of avoiding frequent charging and discharging of energy storage, improving the transmission power of the tie line, and reducing the volatility of the transmission power, the tie line asset utilization is expected to be improved. In order to comprehensively consider the energy storage life and tie-line asset utilization index, this paper adopts the target membership function and uses the maximization satisfaction index method to transform the multi-objective problem into a single objective for optimal solution. Finally, a numerical example is analyzed based on the Nanji Island micro-grid to verify the correctness and validity of the proposed scheme.