The current conventional cost manage- ment model of power grid operation has the problem of single cost apportionment standard, which leads to the poor attribution accuracy. In this regard, the cost attribution method of grid equipment maintenance cost under multi-dimensional lean management mode is proposed. The whole life cycle cost of grid equipment operation is analyzed, and the total cost of grid equipment asset operation and maintenance is calculated, and finally, the operation cost method is used to construct the cost attribution model of maintenance cost. The analysis of the experimental results shows that when the proposed method is used to attribute the maintenance cost cost, the attribution error value of the method is low and has a more desirable cost attribution effect.