The invention belongs to the field of chemical technology and particularly relates to a method for recycling high-purity trifluoroethylene from a tetrafluoroethylene byproduct. The method comprises the following steps of: (1) recycling a fraction containing trifluoroethylene, some tetrafluoroethylene and other heavy components at the top of a tetrafluoroethylene recycling tower through a rough separation tower, and rectifying and separating to obtain a fraction containing trifluoroethylene and tetrafluoroethylene and a high-boiling-point fraction; (2) feeding the fraction containing trifluoroethylene and tetrafluoroethylene obtained in the step (1) into an extraction rectifying tower, and adding an ionic liquid extraction agent for extraction rectification, wherein tetrafluoroethylene is obtained from the tower top of the extraction rectifying tower, and a mixed component of the extraction agent and trifluoroethylene is obtained from the tower kettle of the extraction rectifying tower; and (3) feeding the mixed component of the extraction agent and trifluoroethylene obtained from the tower kettle of the extraction rectifying tower into an extraction desorption tower for desorption, wherein a trifluoroethylene product with purity of not less than 99.99% and polymerizable impurity content of lower than 50ppm can be obtained from the tower top.