The fluctuation and randomness of the output of distributed generation will cause voltage fluctuation when it is connected to the distribution network. We propose a voltage fluctuation suppression strategy based on flexible multi-state switch（FMSS） using its flexible control ability to reduce voltage fluctuation. Firstly

by analyzing the influence of distributed generation and flexible multi-state switch output on the voltage profile of distribution network

we elaborate the principle of FMSS to suppress voltage fluctuation. Then a distribution network operation model with FMSS is established

in which the operation state of distribution network and FMSS are taken as constraints and the minimum voltage fluctuation as objective function. The optimal solution is carried out by particle swarm optimization（PSO）

and a chronological voltage fluctuation index is proposed. Moreover

a three-port FMSS connecting three IEEE33 nodes network is taken as an example to verify the feasibility of the proposed strategy through simulation experiments. The simulation results indicate that the proposed strategy performs a good effect on restraining the voltage fluctuation of distribution network with distributed generation access.