The invention relates to a commutation failure blocking method based on a dynamic reclosing sequence. The method comprises the following steps: 1, when an alternating current system of a receiving end power grid breaks down, a fault time t0 is recorded; 2, whether a commutation failure is caused by the alternating current failure is judged, if no, a direct current does not need to be blocked; and otherwise, the result that commutation is failed is determined, and a step 3 is executed; 3, a breaker is opened and performs an automatic reclosing operation at a reclosing setting time T, if reclosing is successful at the time t that is equal to the sum of t0 and T, it indicates that the alternating current fault is an instant fault, the direct current does not need to be blocked, and otherwise, the alternating current fault is determined to be a permanent fault, and the step 4 is executed; and 4, reclosing is performed when there has the permanent fault, the breaker is failed to be reclosed and is opened again, whether the commutation is continuously failed at the time t that is equal to the sum of t0, T and t1 after waiting for the time t1, if the commutation failure is ended, it indicates that the commutation failure is automatically recovered under the support of other alternating current system voltages, the direct current does not need to be blocked, and otherwise, it determines that the continuous commutation failures occur at the direct current, and the direct current is blocked.