Based on strategic management theory and social capital theory, this study explores how market orientation play its role in new ventures network ties building from an ambidexterity perspective, and reveal the influence mechanism between market orientation (proactive and responsive market orientation) and network ties (political tie and business tie). Through introducing environmental dynamism as moderating variable, this paper explores how Chinese context influence new ventures carry out business activities. After collecting data from 442 new ventures, this study examines the above relationships among proactive market orientation, responsive market orientation, political tie, business tie and environmental dynamism. Empirical results show that both proactive and responsive market orientation positively influence new ventures building political tie and business tie; environmental dynamism positively moderates the relationship between responsive market orientation and network ties (political tie and business tie); but environmental dynamism negatively moderates the relationship between radical market orientation and network ties (political tie and business tie). The results are helpful for new ventures building networks under conditions of Chinese transitional economy and responding to the unique entrepreneurial environment.