With the rapid development of underwater optical communication, sensing and ladar, it is important to deeply understand the effect of oceanic turbulence on beam characteristics. The characteristics of coma beam propagating through the oceanic turbulence are studied by numerical simulation. It is shown that the comet-like beam shape disappears due to the oceanic turbulence. The position of mass center dose not coincide with the position of the maximum light intensity. The beam width calculated on the condition that the position of mass center is regarded as the center is smaller than the result calculated on the condition that the position of maximum light intensity is regarded as the center, but it suffers more from the oceanic turbulence. It should be mentioned that, when the energy Strehl ratio is chosen as the characteristic parameter, the larger the coma aberration coefficient is, the less the influence of the oceanic turbulence on the beam energy concentration is. If we choose β parameter as the characteristic parameter, the energy concentration suffers most from the oceanic turbulence when certain value of the coma aberration coefficient is adopted, which should be avoided in practice. Moreover, the physical meaning of the energy Strehl ratio is different from that of the β parameter. The influence of oceanic turbulence on the energy concentration defined by the energy within a given bucket radius (i.e., energy Strehl ratio) is different from that defined by the certain power percentage (i.e., β parameter), which should be paid much attention in practice.