A hybrid UHVDC transmission system cascaded by a Line Commutated Converter (LCC) and Voltage Source Converters (VSC) at the receiving station can prevent power interruption caused by commutation failure of the LCC at receiving station. The connection control modes become more flexible and diversified. Current which depends on a low voltage control strategy based on the DC and AC voltages of the receiving terminal and an LCC for the limiting voltage control strategy are proposed for AC fault crossing at the receiving station. To obtain stable operation of multi-converters, a power coordination control strategy of multi-converters and a VSC online inputting/quitting strategy are proposed. A crossing strategy based on DC voltage deviation control is proposed for DC line fault crossing. A simulation model is constructed for the hybrid UHVDC system cascaded by LCC and VSC using an electromagnetic transient program (PSCAD/EMTDC). The simulation results show the validity of proposed control strategies. This work is supported by the Science and Technology Project of the Headquarters of State Grid Corporation of China “Research on DC Line Fault Protection and Self-adaptive Coincidence Method for Hybrid Multi-terminal HVDC Transmission System” (No. 52170218000M).