For two linearly bidirectional coupled unified chaotic systems，based on adaptive control technique, the anti-synchronization is completely realised. The adaptive-controller and the coupling coefficient are both estimated by the Lyapunov stable theorem and the minimum value theorem. This method can realise anti-synchronization, not requiring to know the scope of the coupling coefficient and the maximum value of the coupling chaotic systems. We apply this criterion to the case of the coupled Chen-Chen system to test our method，the numerical simulations illustrate that this method has a good performance.