A rational planning scheme for distributed generation（DG） in the distribution network is of great significance for bringing the benefits of DG into full play and restraining the negative effects brought by DG. The sitting and sizing problems of DG in distribution systems are investigated and a multi-objective fuzzy optimal model is proposed that takes into account minimizing the investment cost of DG and the power loss of distribution network and maximizing the static voltage stability margin. The multi-objective planning is transformed into single objective planning by employing the fuzzy optimization theory. Owing to an increase of the short-circuit current level（SCL） due to DG， the maximum SCL limit is taken into account in the constraints. The fault calculation principle in the distribution network with DG is analyzed. As DG has the intermission characteristic， a spinning reserve constraint is included in the model， that is， the distribution substation can supply sufficient power to meet load demands should any DG unit quit. The feasibility of the method proposed is shown by an example of a 43-bus distribution system.