Using the high power multimode pumping method, the Er/Yb co-doped double clad fiber (EYDCF) two-stage master oscillation power amplification (MOPA) based on all-fiber configuration is experimentally studied. With continuous wave (CW) amplification, the maximal output power is 1.52 W, the degree of stability is 0.4% and the slope efficiency is 29%. While with 2 kHz pulsed amplification, the maximal output power is 1.1 W, the degree of stability is 0.45% and the slope efficiency is 25%. The fact that the slope efficiency and the power conversion efficiency (PCE) of pulsed amplification are lower than the CW is caused by the appearance of the Yb3+ band, and the accumulation of the Er3+ band ASE deduces from the output spectrum and time domain waveform. The gain of the amplifier decreases seriously as the input power increases under the high power amplification condition. The impact that the fluctuation of the pump spectrum with the driven current on the amplifier performance is also analyzed.