In consideration of the requirements of a large ground-based high resolution imaging telescope for the Wave-front Processor (WFP) of an adaptive optical system in output scales, processing speeds and control bandwidths, an adaptive optical system with thousand elements was explored. The adaptive optical WFP was composed of a master control computer, a wave-front processing host board and expandable wave-front processing sub boards and its output scale could reach the maximum of 1 200 elements. Large-scale logic devices were adopted as main processing chips, and a multithreading parallel pipeline algorithm was used to shorten the wave-front processing delay and promote the controlling bandwidth of the system. Then, an open loop experiment based on 961-element deformable mirror and a closed corrected experiment based on 137-element deformable mirror were performed. The result shows that the wave-front processing delay is 20.96 μs when the maximum sampling rate is 2000 frame/s，which demonstrates that the hardware expending circuit and multithreading parallel pipeline algorithm are feasible and effective for the wave-front processing of the adaptive optical systems.