The invention provides a customizable position privacy protection method and system based on a user portrait, and the method comprises the steps: firstly, constructing a decentralized communication network, obtaining the position of a stay point in a movement track of a user, and querying the semantic information of the position from a position server through the decentralized communication network; secondly, portraying the user from two aspects of basic attributes and psychological characteristics of the user, and quantifying privacy requirements of the user through the characteristics of the user; and finally, according to the privacy demand of the user, the position server carries out privacy intensity recommendation on the user, and the local end carries out personalized dynamic adjustment according to the local real-time scene information of the user. According to the method, the customized dynamic protection of the user position data can be realized, the problem that the leakage of sensitive position information of the user cannot be effectively solved in an actual position social network environment is solved, and the personalized experience of the user is improved.