Using Software and information service enterprises Cross section data and Tobit model, this paper tests the relationship of the R&D and influence factors, including enterprise scale, ownership type, government subsidy etc. We find that R&D investment and enterprise scale has a U-type relationship, there is no significant difference between the SOE and other ownership types enterprises in the R&D investment, age and profit rate have significant negative effect on the R&D, government subsidy is benefit to the R&D, export and capital intensity have no significant relationship with the R&D investment.