The oven controlled crystal oscillators (OCXO) with SC cut quartz crystal overtone resonator require a band-pass circuits containing inductances to suppress B mode oscillation, which is unfavorable for the miniaturization of OCXOs. In this paper, the vibration model and the calculation model of equivalent circuit parameters of quartz crystal resonators were established in this paper. The discrepancy of normal current density distribution of the B mode and the C mode inside the electrode is used to tailor the electrode, and the B mode suppression electrode was designed to adjust the piezoelectric coupling efficiencies of two modes. A 19.2 MHz 3rd overtone SC cut crystal resonator with B mode suppression was successfully designed. The results show that the proposed method is helpful for miniaturizing OCXOs with SC cut quartz overtone resonator and achieving higher performance.