This paper firstly obtains the formula of the scintillation index for weak and strong turbulence channels on the basis of the power spectrum function of oceanic turblance refractive index and strong fluctuation theory. Then, the average bit error rate (BER), average channel capacity, and outage probability of the oceanic wireless optical communication system are deduced based on the unified Málaga model. The numerical results show that fluctuations in temperature and salinity always have a significant effect on the scintillation index. When the average temperature of seawater is over 20 ℃, the variation of local average temperature has little effect on the scintillation index. The average BER, average channel capacity, and outage probability performance of the wireless optical communication system under strong turbulent channel are worse than that in the weak turbulent channel, and it can be considered to be the strong turbulent channel if the inner scale is less than 0.001 m.