Do I have to submit separate visa applications to travel to Reunion Island and Martinique Island in France?

no. French overseas departments and overseas territories include the following areas: reunion island, French Polynesia (Tahiti), GuaTrop, Guiana, Martinique and Mayotte. China citizens only need to apply for one visa to go abroad, so it is not necessary to submit separate visa applications to travel to Reunion and Martinique in France. Visa is a kind of permission certificate issued by a government agency of a country for foreigners applying for entry, exit or passing through the country in accordance with the provisions of domestic laws.