Abstract: A transmission structure of a coreless tubular motor includes a motor main body, a motor connecting seat, a primary gear ring, a primary planetary gear assembly, a brake outer sleeve, a secondary planetary gear assembly and a tertiary planetary gear assembly; the motor main body is a coreless motor; a brake driving member and a brake driven member which are coaxially provided are provided in and pass through the brake outer sleeve; the brake driving member is connected to an output end of the primary planetary gear assembly, the brake driven member is connected to an input end of the secondary planetary gear assembly, the brake driving member is in transmission connection with the brake driven member, and a braking assembly connected to the brake driving member and the brake driven member is provided on the inner side of the brake outer sleeve in the circumferential direction.