When independent research institutes such as universities transfer their new technology by technology market,asymmetric information caused by uncertainty in value of technology will reduce the efficiency of exchange. As providers of new technology,these independent research institutes exist in the technology market for a long time. Based on it,this paper discusses mechanism of reputation and its effect on efficiency of technology exchange by building up a model of repeated game between a research institute and potential users of technology. It shows that the extent of loss of efficiency is tightly related to the of research institutes’ strength to research. When a research institute can get new technology on strength of research, its concern on reputation can promote it laying a part of low value technologies aside at least. Simultaneously, the result provides an analysis on how national centers of technology transfer promote technology.