A mathematical model that describes the rotation speed regulation process of a main engine system is established. Then an adaptive control system is designed for the control of main engine rotation speed. The adaptive control system makes self-organizing through modification of its weighted values which are determined through correlative search, as well as a coefficient of smoothness is adopted to smooth the process of the weighted value modification. The adaptive control system contains a fault treatment algorithm which is able to maintain stability of main engine operation when the rotation speed regulation system operates in abnormal conditions. The result of simulation experiment shows that the application of designed adaptive control system is able to make the main engine rotation speed regulation process more effective.