The influence of controllable hybrid reactive power compensation on the transient characteristics of transmission lines needs to be studied urgently. Compared with conventional transmission lines, the actual breaking conditions of ultra high voltage(UHV)transmission line circuit breakers with controllable hybrid reactive power compensation are more stringent, which pose a great threat to system insulation. The most serious over-standard condition of transient recovery voltage of UHV controllable hybrid reactive power compensation line is taken as the research object. An equivalent model for single-phase grounding faults in UHV hybrid reactive power compensation lines is established, and the influencing factors of transient recovery voltage are analyzed. The transient recovery voltage(TRV) suppression measure of controllable hybrid reactive power compensation line is proposed. By combining the theoretical analysis of equivalent parameter lumped circuit with PSCAD/EMTDC simulation, the suppression effects and feasibility of fast linkage bypass series compensation, circuit breaker with opening resistance, and fast grounding switch on transient recovery voltage are discussed, and the best suppression measure of transient recovery voltage is obtained, which provides a practical reference for UHV engineering construction.