In optical satellite network,standardized transmission mode is reliabl e guarantee of efficiently processing and transferring multi-sources data in existing space link.Transmis sion frame reframing unit (TFRU) is proposed to solve the problem that different sources data have low transmission efficiency in laser link.TFRU uses virtual channel (VC) technology to unify format and rate of the transmissio n data by second encapsulation and VC scheduling for sources data.The priority VC scheduling algorithm is proposed to further improve multiplex efficiency.According to the principle of TFRU encapsulation and the arrival rate of sources data,the frame dynamic priority is defined by VC priority and frame criticality.And the specific metho d of priority VC scheduling is provided.Simulation results show that the throughput increases by 3.0546M and the scheduling time delay reduces by 0.9183s,so the system performance has been greatly enhanced. Cac he demand is satisfied as the TFRU transmission rate is larger than the sum of all sources data rates.Through d ynamicall y scheduling generation of TFRU frames,the priority algorithm based on TFRU ensures scheduling fairness of the f rames in each VC.