The size of technical spillover is influenced by the innovative cooperative degree between firms, and technical spillover is not only the single-part choice for the enterprise which conducts innovation but also is the result of mutual technical path choice combination of the enterprises. Based on the assumption that “the more compatible the technology between firms is, the higher the technical spillover is”, innovative technology decision is integrated into duopoly game model to comparatively analyze the motive and influence of firm innovative technology selection, and the results show that whether cooperation or non-cooperation, the enterprises which pursue profit maximization always choose identical or similar technical innovation, however, social optimal technology difference is higher than the technology difference of profit maximization, thus, in the industries which have high technical spillover, non-cooperative model may result in relatively low social welfare and so governments should encourage innovative alliance or patent-chain-business.