A 50 W class, high power 808 nm laser diodes double-end-pumped Nd∶YVO4 composite crystal laser oscillator is reported. The adoption of double-end-pumping configuration and composite crystal can effectively alleviate thermal effect and achieve more uniform thermal and gain distributions in the laser crystal. Asymmetrical plane-plane dynamically stable resonator is employed, which can make the two stable zones separated. Making the laser operated in stable zone I, we can pump the laser crystal with high pump power and get very small misalignment sensitivity, which are favorable for high power output and resonator’s mechanical stability. After optimizing the length of the two cavity arms, we obtain 51.2 W continuous-wave (CW) TEM00 mode laser output with about 104 W pump power, corresponding to an optical-to-optical efficiency of 49.2%. With an acousto-optic (AO) Q-switch inserted into the resonator, pulsed laser can be obtained within the pulse repetition rate range of 50～600 kHz. Within the pulse repetition rate range of 100～600 kHz, the average output power is stable at 49 W and the pulse width changes from 18.2 ns to 85 ns. At a pulse repetition rate of 50 kHz, the average output power reduces to 43.2 W with pulse width of 13.5 ns and peak power of 64 kW.