Thanks to the advantages of compact, inexpensive and high conversion efficiency, high power fiber lasers are highly desired in industry applications. Recently, an all-fiber high power fiber amplifier directly pumped by laser diodes (LDs) was experimentally established. A maximum power of 20.27 kW was achieved with the optical-to-optical efficiency of 84.8%, central wavelength of 1080 nm, and Raman-suppression ratio of >50 dB. We believe that the brightness and the output power can be further improved by optimizing the design of the Yb-doped fiber and devices.