Innovation is a key factor in creating and maintaining competitive advantages for new ventures. How do innovation modes within a new venture interact with each other and how can external relationship networks co-evolve? These issues are important for the survival and development of new ventures. Therefore, this paper analyzes the dynamic choice of the innovation modes in depth from the perspective of the dynamic evolution of the new enterprise life cycle, and on this basis, develops the strength of the different relationship networks. By theoretical deduction it comes to the following conclusions: during the creation period, the new ventures will choose the technical innovation and expand the strong relationship network; during the survival period, they choose technological innovation accompanied by organizational institution innovation, and expand the weak relationship networks; growth period, they choose organizational institution innovation accompanied by technology innovation, and transform weak relationship networks to strong relationship networks. Therefore, the new ventures should take appropriate innovative ways and develop the relationship networks in accordance with the stages, then to enhance innovation performance. This paper helps to expand the innovation theory, promote the innovation research of the new ventures, and provide the theoretical guidance for the new venture growth.