The invention discloses an anti-eavesdrop and anti-interference spectrum access method based on bandwidth and power distribution. According to the method, in order to prevent an eavesdropper from eavesdropping information of a main user, a sending end of a main system sends artificial noise through a part of power and sends signals through remaining power, and meanwhile a receiving end of the main system sends artificial noise so that so that a sending end of a secondary user cannot be influenced by the artificial noise when receiving the signals of the main system; if the main system can reach a target safety rate with the help of a secondary system, the secondary system is allowed to conduct spectrum access; after the secondary system conducts spectrum access, a part of bandwidth is used for helping the main system forward information so that the main system can reach the target safety rate, and the remaining bandwidth is used for sending the information of the main user. By means of the method, mutual interference between the main user and the secondary user is effectively eliminated, and safe transmission of the information of the main user is ensured.