Under the trend of globalization, the enterprises are facing rapid environmental change and the key to survival and success is to enhance competitive advantage. Meanwhile, the development of the high tech and popular of the information tech result in the information service has become one of the most important industry. It is not only huge market opportunity, but be also relevant of the increasing the competitive of the other industry. The phenomenon causes the industries of the world invest to develop the information heavily to obtain competitive advantage. Therefore, the study explores the effect of demand management on the project performance and to figure out the significant difference of the demand management degree of project types. Data was collected from the 108 valid questionnaires of the domestic information service personnel. The results show that demand management had positive effects on project schedule, cost, and quality. Accuracy and confirmation of project demand had positive effects on project efficacy. Also the recovery higher project complexity was found that had significant difference from the lower project complexity. Higher project cooperation relationship had significant difference from the lower project cooperation relationship. Both theoretical and practical implications are discussed.