Combination of multiple laser beams provides an effective approach for achieving high power laser beam with high energy, so beam combination technologies have been widely investigated for the past years. Recently, with the development of practical application requirement such as free-space optical communication and laser propagation engineering, the propagation properties of combined beams through atmospheric turbulence gradually become hot issues in the field of light propagation. Firstly, the comparison of various techniques including extended Huygens-Fresnel principle, Rytov perturbation approximation and numerical simulation is conducted, according to various combined beams that are composed by multiple typical laser arrays. Secondly, some methods for estimating the beam quality of combined beams are listed, such as power in the bucket (PIB), β factor, M2 factor and beam propagation factor (BPF). Finally, some problems that should be further studied according to investigation actualities and main results of combined beams are presented.