This paper proposes an economic dispatch strategy for micro-grid based on the sequential quadratic programming (SQP) method. In this paper, in the off-grid operating state, according to the load, the kinds of micro sources and the operating cost, the power output minimizing the operating cost is calculated. When the system is connected to the grid, considering the tiered price, generation cost of CHP (Combined heat and power) based on micro-turbine, and generation cost of fuel cell, the paper calculates micro source power output based on the minimum operating cost. The characteristics of the proposed model and its benefits are investigated through several case studies.