In the global market economy, most power consulting enterprises in Vietnam have many engineering investment projects. The successful implementation of investment projects is a vital part of their business. For projects to succeed, CEO and leaders in those firms must make the right criteria for evaluating projects. In real practice, it is not an easy task because there are many factors that influence the success of a project such as time, cost, quality, and the satisfaction of stakeholders, etc. Assessing the importance of these project success criteria is a complex multi-criterion decision problem. On the other hand, traditional assessment methods are often based on t customarily based on subjective opinions of the decision maker, resulting in the wrong decision. Therefore, this paper presents a new fuzzy decision-making method for weighting project success criteria in power consulting companies in Vietnam. This new method is expected to provide an objective measure in project success appraisal process.