To improve the performance of underwater wireless optical communication, a scheme is proposed to increase the bandwidth of underwater optical communication through the multiplexing of vortex beams, and at the same time improve the attenuation length supported by the underwater optical communication by using photon-counting detection. The examination results show that information transmission was achieved in the coastal seawater channel with a slight error rate below the forward error correction threshold, thus verifying the feasibility of the scheme. The transmission power of the communication system is only 3.21 nW after the photon-counting scheme is adopted. Considering only the attenuation of light intensity by the water channel, the supported attenuation length reaches 20.21 in the underwater optical communication system with vortex beam when the transmission power is increased to 1 W. This experiment provides a solution for underwater optical communication that can simultaneously increase the information transfer rate and attenuation length.