Since14th century, Japanese pirates have been invading Hainan Island. Then, the Japanese arrived in Qiong in an endless stream. 1February 1939, the Japanese illegally occupied Hainan Island until1August 1945, when Japan surrendered. This paper reveals the history of Japan's invasion of Hainan Island by using Japanese literature and history archives, and points out that in the historical research of Hainan Island, the use of Japanese first-hand materials at home and abroad is far from enough.