The recently emerged Reconfigurable Intelligent Surface (RIS) technology can realize the reconfiguration of the wireless environment, thereby improving the performance of wireless communication systems. Therefore, it has attracted the attention and research of many scholars. Based on this, this paper studies the method of RIS to enhance the security of uplink non-orthogonal multiple access (NOMA) communication systems. Our objective is to maximize the secrecy rate of the system by jointly optimizing the user transmit power, the receive beamforming at the base station (BS) and the RIS phase shift matrix. In order to make the original extremely complex non-convex problem tractable, we use an alternating algorithm to transform the original optimization problem into three tractable sub-problems. Among them, sub-problem 2 and sub-problem 3 are solved by fractional programming (FP), Dinkelbach algorithm, majorization-minimization (MM) algorithm, and Lagrange multiplier method respectively. Finally, the numerical simulation results verify that the scheme proposed in this article can significantly improve the secrecy rate performance of the communication system.