A mathematic model for distribution network dynamic optimization considering reconfiguration times is presented and then a switch group-based Tabu algorithm is proposed to solve this problem. The codes of decision variables are composed of two parts， i.e. net frame section and time section. One hand the net frame section is made up of switch group status， which considerably reduces the dimensions of decision variables and the number of infeasible solutions. On the other hand the ternary number system is used in time section， which uniforms the value range of variables and facilitates the determination of Tabu table length and termination condition. In addition， the neighborhood searching in Tabu algorithm is instructed by forbidden rules， which not only reduce the number of candidates， but also avoid the occurrence of dead circle， thus promoting the searching efficiency and quality. At last， comparisons between the new algorithm and other algorithm are made to verify the new one's speed and effectiveness.