Abstract: The present invention provides an internal three-speed dual-clutch transmission, comprising a housing module, an intermediate shaft module, a planetary gear module, a driver module, a main clutch module, an auxiliary clutch module, a jack cage module and an outer gear ring module. The housing module comprises a housing, a brake adapter and a housing adapter and is configured as an output end; the intermediate shaft module comprises an intermediate shaft, a push rod, a steel ball track nut and a frame locking nut. The planetary gear module comprises at least one planetary gear, a planetary gear cage, at least one planetary gear cage pin shaft and at least one planetary gear cage jack. The push rod serves as a speed-changing push rod, the auxiliary clutch module acts as a clutch switch, and the main clutch module has the function of the clutch switch and transferring torque.