This paper proposes an efficient method for distribution network expansion planning under new environment. The proposed method optimizes the distribution network expansion planning with two-layered tabu search that considers different neighborhood creation. In this paper, a new network expansion planning method is presented to consider distributed generation and the outage cost in distribution systems. The problem formulation may be expressed as a more complicated combinatorial optimization problem. As a result, a new technique is required to solve the problem. This paper proposed a two-layered tabu search that deals with the optimal location of distribution generation at Layer 1 and the feeder and substation at Layer 2. The technique allows tabu search to handle different types of integer variables. The proposed method is tested in a sample system.