Studying lead users can understand future market development trends and capture user needs, develop new products and services with more market potential and so on, and increase the competitive advantage of the company's new products or services. But the relevant research is not yet mature, and domestic research is very scarce. Based on the relevant foreign language databases, this study sorts out the important results of theoretical research of lead user, and analyzes in depth the concept, scales, measurements, and influencing factors. Results show that: first, lead users are individuals that are at the forefront of trends in important marketplace (ahead on an important marketplace trend) and expect high benefit from obtaining solutions to their needs (high expected benefits); second, the scale includes two basic dimensions of ahead on an important marketplace trend and high expected benefits; third, the antecedents of lead user consist of field-related variables, field-independent variables and motivation. Finally, the prospect of future research is prospected in order to provide references for domestic scholars to further study lead users and enterprises cooperate with lead users in new product development.