A two-end pumping high power continuous-wave (CW) Yb3+-doped double-clad fiber laser was reported. In experiments, two types of laser diodes with center wavelength around 975 nm were adopted as pumping sources, and the characteristics of output power and laser spectrum were measured under different pumping conditions. Under the pumping of the pigtailed laser diode, output power was 9.2 W, slope efficiency was 42% and laser peak spectrum was 1103.8 nm. Under the pumping of the collimated laser diode, output power was 20.0 W, slope efficiency was 57% and laser peak spectrum was 1104.4 nm. When both laser diodes were used to pump the fiber laser together, the maximum output power of 30.6 W, laser peak spectrum of 1108.4 nm and total optical-to-optical efficiency of 49% were achieved.