The model of high-power LD pumped laser array is established and based on slab laser and fiber laser, two typical high-energy LD pumped laser systems, coherent- and incoherent-combining types, are analyzed and compared. The influence of atmospheric turbulence on far-field beam quality of coherent and incoherent laser beams of these two lasers is evaluated quantitatively with the beam propagation factor (BPF) to characterize the beam quality. The mathematic model and calculation result can provide a reference for choosing and evaluating different combining schemes.