To solve a problem of failure of the traditional commutation failure prevention method for a UHVDC hierarchical access system, a coordinated control strategy based on DC current control is proposed. Based on the in-depth analysis of the primary and secondary factors of the commutation failure, the strategy detects the AC system failure and triggers the non-fault layer commutation failure prevention control in advance according to the output of the failure layer commutation failure prevention control. At the same time, it instantaneously reduces the DC current at the initial stage of the failure, which increases the immunity to commutation failure of the non-faulty layer, and improves the subsequent commutation failure of the faulty layer. The UHVDC hierarchical access system is built in PSCAD/EMTDC. Simulations show that this strategy can effectively suppress the commutation failure of the non-faulty layer and the subsequent commutation failure of the faulty layer. This greatly improves DC power transmission during the fault period and is conducive to the safe and stable operation of the power system. This work is supported by the National Natural Science Foundation of China (No. 51977135).