Abstract: After the Meiji Restoration, Japan quickly embarked on a path of external expansion. During its aggression, Lew Chew became its first target due to geographical factors. As a vassal of China, Lew Chew’s minister had to seek help from the Qing government to resist Japanese aggression during the critical time. The main policy of the Qing government in handling this issue was to actively seek the help of various powers in diplomacy. At the request of Li Hongzhang and others, former US President Grant became the mediator of the Lew Chew dispute. After years of continuous negotiations between China and Japan, Japan finally came up with a so-called “Island Division Treaty”. However, there is still controversy over whether this plan originated from the Qing government, the Japanese cabinet, or Grant, and whether Grant directly intervened in the “Island Separation Treaty” in the academic community. Although Grant did put forward the spirit of “mutual concessions”, but the actual treaty formulation and final implementation plan should have been achieved with the promotion of the Japanese cabinet, ultimately ending with the Qing government’ refusal to sign it and Lew Chew being fully occupied by Japan. Therefore, Grant’s role in the Ryukyu dispute was to provide room for negotiation and ease between China and Japan, and based on similar cases in the West, he proposed a mutually compromised negotiation according to the “Grant Spirit”, which did not directly intervene in the formulation of the “Island Division Treaty”. Seen from this perspective, Grant’s role in this event may be more objective and clearer.