The invention discloses a 110 kV cable connector operation overvoltage characteristic estimation method comprising the following steps: 110kV three-phase cables are completely symmetrical in case of normal closing and three-phase circuit breakers are fully synchronized, the equivalent circuit is obtained when the no-load line is switched on, the effect of power supply and circuit resistance is omitted, the no-load line is replaced by the T-shaped equivalent circuit, LT and CT are the equivalent inductance and capacitance of the line, the power supply potential is Emcosomegat, and then the equivalent circuit can be simplified as a single oscillation loop; when t=0, the no-load long line with zero initial voltage is connected with the AC power supply e (t) = Em(cosomegat + theta), the head voltage U1 (S) of the line after closing and the end voltage U2 (S) of the line after closing are obtained by using Laplace transformation, and the operation overvoltage u2 (t) at the end of the 110 kVcable after closing is obtained by using the decomposition theorem. The operation overvoltage at the end of the 110 kV cable can be estimated by the method.