Inspired by the technique development of solid-state lasers cooled by liquid directly, the phase aberrations at laser wavefront induced by the turbulence in channel flow is investigated theoretically. By means of the statistic characteristic of the channel-flow turbulence, a method to model the laser phase-screen induced by turbulence in channel flow is proposed. Within the assumption of incompressible fluid, there are two kinds of turbulence thermal mechanics, which are heat transfer of transport and heat generation of dissipation, that generate temperature fluctuations in both temporal and spatial regions, and further generate the phase screen induced by the channel-flow turbulence. The numerical result shows that the degeneration of beam quality is mainly caused by heat transfer of transport instead of heat generation of dissipation. The phase aberration induced by the density fluctuations is discussed as well.