Abstract: The present disclosure provides a method for inducing a lateral branch development of Eucheuma denticulatum, and relates to the technical field of marine organisms. In the present invention, the E. denticulatum is subjected to aeration culture at a light-photon flux of 200 ?mol·m?2·s?1 to 300 ?mol·m?2·s?1. During induction with a high light intensity, new lateral branches continue to grow; after the high-light treatment is completed, the E. denticulatum is placed in its original breeding environment. The dedifferentiation of branch cells into meristems is induced by the high light intensity in E. denticulatum, and then the meristems are developed into lateral branches. An increase of the lateral branches can increase a yield of E. denticulatum, and the high-light treatment can significantly increase a dry matter content of the E. denticulatum to raise an income.