The invention discloses a control parameter optimization method for improving the phase commutating failure restraining capacity of a direct current system. The method comprises the following steps that after initialization, through an interface technology between PSCAD and MATLAB, a first interface module and a second interface module are established, the first interface module is used for calling an optimization algorithm, a whole iteration function of the algorithm is carried out, when each-time simulation is started, through an improved particle swarm algorithm, particle positions are updated, and controller parameters are returned to the PSCAD; and the second interface module is used for receiving the particle positions returned by the PSCAD and optimizing target functions after each-time simulation is over, and the global optimum particle positions and the individual optimum positions are updated. Through the interface technology between the PSCAD and the MATLAB, combining calling of the PSCAD and the MATLAB is achieved, the improved particle swarm algorithm is used for searching for the optimum control parameters, a multi-time operation function in the PSCAD is used, calling of multi-time software can be achieved, and accordingly optimization searching of control parameters is achieved.