As the deep penetration of oil field, the requirements of technological innovation capability from production enterprises have become higher and higher. Therefore, in this paper, mathematical base for establishing evaluation model of technological innovation capability has been analyzed firstly; secondly, according to the concept of entropy from information theory, mathematical model for evaluation of technological innovation capability in oil field has been established, which set up 19 index systems from three respective. Finally, 16 years' data sample size from a grassroots unit have been collected and analyzed. Quantization has been obtained; the result has met the law of development of technological innovation in oil field enterprises.