Embodiments of this application provide a wireless optical communication method and a communications apparatus, and relate to the field of mobile communications technologies. The method includes: receiving a data frame sent by a second device; obtaining coded symbols, lengths of source symbols, a quantity of source symbols, degree information of the source symbols, and index information of the source symbols based on the data frame, where the degree information of the source symbols indicates a quantity of source symbols included in each source symbol group that participates in coding processing, and the index information of the source symbols indicates indexes of the source symbols included in each source symbol group that participates in coding processing; determining a mapping relationship between the source symbols and the coded symbols based on the lengths of the source symbols, the quantity of source symbols, the degree information of the source symbols, and the index information of the source symbols; and determining the source symbols based on the mapping relationship, the coded symbols, and a preset rateless decoding algorithm. According to this application, bit rate adaptation can be implemented based on a dynamic channel at a VLC physical layer.