Abstract: With the large-scale application of DC/DC converter in DC distribution systems, the delay of feedback signal makes it difficult for converters to receive real-time signals, and the delayed converter control may cause the load side voltage instability under the delay state. However, the voltage instability cannot be completely avoided because the time delay is random. This paper proposes an optimization strategy based on the constraint of norm condition. The optimization strategy in this paper ensures the stable operation of the time-delay system, and greatly maintains the response ability of time-delay system. First, this paper analyzes the system stability in phases, and the key point of stabilization to the time-delay system in the unreasonable parameter of the voltage loop control. Then, this paper constructs the norm inequality about voltage disturbance and response, and the optimal controller parameter is found with the Lyapunov function verifying the norm inequality. Finally, a smart and new energy microgrid in Shanxi province is studied as a case. The comprehensive performance of the system is compared by the parameter before and after optimization. Therefore, the effectiveness of the optimization strategy is verified.