Embodiments of the invention disclose a distributed data transmission method and device based on a TM RLC (Transparent Mode Radio Link Control) protocol and a TM RLC entity. A central transmission cache is arranged in the TM RLC entity. The method comprises a step that the central transmission cache sends a TM RLC SDU (Service Data Unit) to a corresponding branch wireless link in a form of TM RLC SUD burst cluster after receiving the TM RLC SDU. The technical scheme of the embodiments of the invention can be compatible with the existing TM RLC protocol stack function and the time delay brought by the discontinuous transmission and has good expansibility to quickly support a large amount of users.