Nowadays, following the requirement of industry-university-research (IUR) deep integration, more and more technology-based SMEs have simultaneously participated in multiple IUR alliances and formed IUR alliance portfolios (IURAP) with different interaction breadth and depth in order to obtain external complementary resources and achieve high-quality rapid firm growth. In this paper, an “IUR alliance portfolio - innovation ability - firm growth” research framework is built, and data of 150 listed manufacturing firms on China’s GEM Board is used to explore the internal mechanism of IURAP breadth and depth on growth of technology-based SMEs as well as the moderating roles of China’s unique formal and informal institutional environments. Results show that: (1) IURAP breadth positively affects growth of technology-based SMEs, while IURAP depth negatively affects growth of technology-based SMEs; (2) IURAP breadth positively affects innovation capability of technology-based SMEs, while IURAP depth negatively affects innovation capability of technology-based SMEs; (3) innovation capability plays partial mediation effects between IURAP breadth and depth and growth of technology-based SMEs; (4) formal institution development level weakens the positive impact between IURAP breadth and growth of technology-based SMEs, and weakens the negative impact between IURAP depth and growth of technology-based SMEs; (5) social trust level strengthens the positive impact between IURAP breadth and growth of technology-based SMEs, but weakens the negative impact between IURAP depth and growth of technology-based SMEs. Conclusions expand research on alliance portfolios, university-industry collaboration, and institution theory, providing practice enlightenments for implementing IUR deep integration strategy in Chinese technology-based SMEs.