We combine nonequilibrium Greens function method with elastic theory to investigate the ballistic thermal transport in graphene nanoribbons under homogeneous uniaxial stretching applied in the longitudinal direction.Remarkable enhanced thermal conductance is found.The enhancement ratios could be up to 17％ and 36％ for the 5-nm zigzag and armchair graphene nanoribbons,respectively.This enhancement effect results from a lot of dispersive phonon modes which are converged to low-frequency region.