InGaAs/InP avalanche photodiodes typically work in the gated Geiger mode to achieve near-infrared single-photon detection. By using ultrashort gates and combining with the robust spike-canceling technique that consists of the capacitance-balancing and low-pass filtering technique, we demonstrate an InGaAs/InP single-photon detector (SPD) with widely tunable repetition rates in this paper. The operation frequency could be tuned conveniently from 100 MHz to 1.25 GHz with the SPD’s performance measured to maintain good performance, making it quite suitable for quantum key distribution, laser ranging, and optical time domain reflectometry. Furthermore, the SPD exhibited extremely low-noise characteristics. The detection efficiency of this SPD could reach 20% with the dark count rate of 2.5×10 6/gate and after-pulse probability of 4.1% at 1 GHz.