This paper seeks to enable the port of Shandong Peninsula to better handle the relationship between competition and cooperation and thus achieve common development. Based on an analysis of the current development of Shandong Peninsula ports, the paper proposes a port competition and cooperation strategy based on a Bertrand game. According to the game model, an income matrix of Qingdao Port and Rizhao Port, Yantai Port and Weihai Port is established and an analysis the income of each port under different strategic combinations is conducted to determine the strategy that is most conducive to the development of the ports. At the same time, we consider the instability of cooperation and establish a certain cooperation mechanism. Finally, an example is used to verify the effectiveness of the proposed port development strategy for Shandong Peninsula.