The traditional efficiency evaluation model considering undesirable outputs is only able to calculate the efficiency of the overall value of the decision-making units. This paper puts forward a new environmental efficiency evaluation based on the proper slack-based measurement (PSBM) model, which can give the efficiency values of the inputs, desirable outputs, and undesirable outputs. The results from the new model are not only highly correlated with SBM-based evaluation results, but also coincide with reality, which can be used to test the effectiveness of the new model. Our model provides more information for environmental efficiency evaluation analysis.