Three power amplifier system is reported in which the Nd∶YVO4 crystal is pumped by laser diode (LD), in which 1064 nm picosecond laser output average power is more than 21 W. When the repetition frequency of 56 MHz, the average power of 3 W picosecond seed pulse is injected, a maximum power of 26 W is got by a three-stage power amplifier system with the optical conversion efficiency of 25%. The picosecond pulse duration is less than 17 ps, power instability in 1 h is less than 2%, and the light beam quality M2 is less than 1.5. A RbTiOPO4 (RTP) electro-optical switch is as a marking switch and the main-minor pulse ratio is up to 2101, which is suitable for the use of the marking machine.