At present, the majority of small- and medium-sized enterprises of science and technology are facing sharp financing dilemma. To explore the economic root of the problem, this paper makes a theoretical analysis and the research demonstrates that: market failure, which is triggered by information asymmetry between bank and enterprise and SMEs signaling obstacle, together with government failure, which is induced by displacement of government function, should be responsible for the financing dilemma. Therefore, in order to reduce information asymmetry between bank and enterprise and give the full play to the function of the government, efforts should be made to develop relationship lending, actively try internet public equity financing, improve the credit guarantee system, perfect the rights of intellectual property and enterprise management right pressure financing service system, issue securities backed by financial intellectual property, establish technology bank supported by policy and develop micro credit guarantee companies and regional small- and medium-sized commercial banks, thus easing the financing difficulties of small- and medium-sized enterprises of science and technology.