The bidirectional output fiber laser can achieve two laser outputs through a resonant cavity structure, which can reduce the volume and cost of high-power fiber laser systems and has good application prospects in the industrial field. Based on the oscillator with bidirectional pumping, employing the double cladding ytterbium-doped fiber (DCYDF) with a core/cladding diameter of 30/400 µm which was pumped by the wavelength-stabilized 981 nm laser diodes (LDs), a bidirectional output fiber laser oscillator with a total output power of greater than 8 kW was achieved experimentally for the first time. With the total bidirectional pump power of 10.951 kW, a total output power of 8169 W with 3769 W at end A and 4400 W at end B were achieved, with an O-O efficiency of 74.6%. No TMI or SRS were observed at both ends, and higher laser output power can be expected by further increasing the pumping power.