Abstract: The signal processing machine for a mini adaptive optics system is described. The signal processing machine consists of a PC computer as the host machine and a TMS320VC549 as the signal processor. With the powerfulness of the PC computer, such functions as the real time display of spot array image, the real time display of wave front, and the test of response matrix of deformable mirror can be realized, while the high speed of TMS320VC549 ensures the bandwidth of the control system. The experiment of the whole system incorporating the signal processing machine and the optical mechanical system has been carried out. The experiment showed that the processing machine fulfils the requirements of bandwidth and precision, and that its functions of real time display and test of response matrix of deformable mirror greatly facilitated the experiment.