As the fact that current equipment maintenance mode selection does not include device health index, maintenance costs and loss of equipment failure, an optimized model considering the above elements for distribution network equipment maintenance mode selection is proposed. The new model defines the loss of risk as the product of the loss and the probability due to equipment failure where the equipment failure loss is consist of equipment asset loss and power loss. The specified calculation formula of each part is given. The composition of maintenance costs, calculation methods and the effects that different maintenance modes have on the equipment failure rates are analyzed. Aiming at the minimum sum of maintenance costs and the risk of loss after repair, a quantified method is employed in selecting the maintenance mode. An example is shown to elaborate the selection procedure of two transformers maintenance modes in certain condition and well proves the effectiveness of the model.