In today's modern transformation of tax affairs, as information technology and Internet technology are constantly updated and become more advanced, it is necessary to reasonably change the processing ow of tax affairs, such as breaking the time and space constraints to make it more convenient. It is an inevitable need to complete the reform and optimize the business environment through the "release, management and service" policy to achieve technological transformation. The big data technology platform can well accomplish the expected tasks, thus providing systematic support for tax work. In this context, this paper integrates the deep learning technology with the big data technology platform to complete the design of the mobile tax system for taxpayers. It is convenient and fast, and can realize the creation of an intelligent tax evaluation system, so as to carry out tax management, information retrieval, information release, user communication and system management, and can also safely repair the system itself. Through the design experiment, the user-de ned query and retrieval function of the system is tested. The results show that the comprehensive query module of the system has good security, and the evaluation system can meet the user's requirements for ease of use and friendly system interface. This paper has completed the construction of smart tax evaluation system by integrating deep learning technology and big data technology platform.