Lost circulation often happens during drilling process, which is not only a severe trouble for safe drilling, but also leads to more complex problems to seriously restrict the exploration and development of oil field. The decision method of leakage zone and the stimulation evaluation on plugging agent formula are introduced in the paper. For formation leakage, the lost circulation zone should be located first, and then the evaluation is made on the plugging agent formulas to decide an ideal formula and the corresponding plugging plan. The success rate of plugging can be increased by this way.