Due to the significance of secure communication, we do a research about this problem based on fractional-order chaotic systems, where a communication scheme is presented for encryption and decryption of the signal. Through applying Lyapunov stability theory and property of fractional calculus, an adaptive sliding mode controller is designed to achieve the synchronization phase between encryption system with encryption source and decryption system, which offers a tool to the decryption process. To improve the precision and speed of the decryption, we further put forward an optimization strategy for some parameters of the developed controller based on root mean square error of certain variable as a performance indicator. Meanwhile, as an improved teaching–learning-based optimization algorithm, teaching–learning–feedback-based optimization (TLFBO) algorithm is proposed to optimize the parameters more excellently. Subsequently, the simulation experiments, which contain performance test for TLFBO algorithm and secure communication of the signal, are, respectively, conducted on the benchmark functions as well as fractional-order Lorenz system with encryption source and fractional-order Lu system. At last, the experiment results illustrate the feasibility and practicability of the provided method by comparing with some other ones.