For the three-terminal line commutated converter-modular multilevel converter (LCC-MMC) hybrid DC transmission system, the DC transmission power reducing or interrupting problem caused by AC side fault at the rectifier station is studied. And an AC fault ride-through coordination control strategy for rectifier converter station is presented. Firstly, the mathematical models of different types of converters are established and the characteristics after AC system faults are analyzed. Secondly, according to the different operation modes and the fault characteristics of DC voltage decrease and DC line contain 100 Hz harmonic, the coordination control strategy between the minimum trigger angle control at rectifier side and the maximum modulation ratio control at converter side is proposed. Thirdly, the original 100 Hz protection values are changed then the control modes can be switched automatically without stations communication. Finally, a hybrid DC transmission system model is established in PSCAD/EMTDC, and the control characteristics of the system under different working conditions are simulated and analyzed. Results show that the proposed control strategy can improve the transmission power of the DC system and reduce the probability of power transmission interruption when short curcuit fault occurs at the rectifier AC side.