The embodiment of the invention provides a dynamic verification code selection method and system, and the method comprises the steps: obtaining terminal state information sent by a user terminal, carrying out the safety performance evaluation of the safety state information of the user terminal according to the terminal state information, and obtaining the safety state information of the user terminal; According to the security state of the user terminal, sending a verification code corresponding to the security state information to the user terminal, Wherein the terminal state information comprises but is not limited to one or a combination of more of network related data, terminal software environment information, terminal hardware information and terminal operation information. According to the safety assessment result, the corresponding verification code is selected and sent to the user terminal, the risk degree of the user terminal is estimated in advance, the safety of the user terminal in the verification process is improved, and meanwhile due to the fact that the verification code difficulty of a user with higher reality can be dynamically reduced, the user experience of acommon user can be improved.