Achieving a high power fiber laser output while maintaining high beam quality is challenging due to the constraints of stimulated Raman scattering (SRS) and transverse mode instability (TMI). In this paper, based on a counter tandem pumping scheme, an output with a power of 8.38 kW and a high beam quality factor of M²=1.8 is achieved in a homemade and conventional double-clad 30 μm /250 μm Yb-doped fiber. The SRS and TMI effects are effectively suppressed, but the further power increase is restricted by the available pump power.