A 19-element serial hill-climbing adaptive optics system is introduced. By using a 19-element def ormable mirror, a detector for sharpness of far-field spot and a dither control system,’ it can correct static and vary slow dynamic wavefront error. The hill-climbing control algorithm, experimental setup and correction effect are reported. Experimental result shows that this system can be used in large laser engineering system for wavefront error compensation and far field sharpness improvement.