This paper studies the method of improving the transmission characteristics of underwater optical communication system based on orbital angular momentum (OAM) by using Humbert beams of type-II (HB-II). Based on the Rytov principle, an analytical expression for the spiral phase spectrum of HB-II beam after passing through the oceanic turbulence is derived, and the influence of different oceanic turbulence and beam parameters on the detection probability of HB-II beams is compared and analyzed. The results show that the detection probability of OAM mode of HB-II beam in ocean turbulence decreases with the increase of propagation distance, topological charge and kinetic energy dissipation rate. The anti-interference ability of the beam in ocean turbulence increases with the decrease of waist width, mean square temperature dissipation rate, and temperature salinity contribution rate. For HB-II beam, the fluctuation of detection probability can be relatively smooth when transmitted at different distances, and the detection probability performance is better than those for Airy beam and Laguerre Gaussian beam. The results can provide theoretical reference for designing the underwater optical communication systems based on HB-II beams.