Based on social capital utility heterogeneity perspective, uses 8 years data of 132 TMT and Internet companies, studies the effect of linking, bridging, combining social capital on innovation output and process mechanism. Experience has proved that social capital makes R&D behavior supports views of relationship innovation, positive correlation between linking social capital and innovation output is the most closely related. R&D investment plays an incomplete mediating role between social capital and innovation output. The differences of company property and financing constraints significantly affect output scale, positive effect of R&D investment is more obvious in enterprises with loose financing constraints or state-owned TMT and Internet companies.