Under the new situation that premeditated and persistent attacks have become the norm, resource-constrained industrial control equipment uses traditional encryption protection methods with fixed encryption strength and faces challenges such as simple stacking of protection capabilities, waste of resources and weak protection capabilities. Firstly, the technical principle of dynamic change of encryption strength driven by attack threat is discussed, and then the technology of adaptive change of encryption strength driven by attack threat (TD-ESAT) is proposed. Experiments and analysis show that in the real-time operation scenario of industrial control equipment, the protection efficiency of this method is significantly improved.