Considering the air-water interface and ocean water’s optical attenuation, the performance of quantum key distribution (QKD) based on air-water channel is studied. The effects of photons’ various incident angles to air-water interface on quantum bit error rate (QBER) and the maximum secure transmission distance are analyzed. Taking the optical attenuation of ocean water into account, the performance bounds of QKD in different types of ocean water are discussed. The simulation results show that the maximum secure transmission distance of QKD gradually reduces as the incident angle from air to ocean water increases. In the clearest ocean water with the lowest attenuation, the maximum secure transmission distance of photons far exceeds the the working depth of underwater vehicles. In intermediate and murky ocean waters with higher attenuation, the secure transmission distance shortens, but the underwater vehicle can deploy other accessorial methods for QKD with perfect security. So the implementation of OKD between the satellite and the underwater vehicle is feasible.