<p>This paper proposes an encoding method based on the characteristics of multi-particle system. Utilizing this encoding method, a robust semi-quantum secure direct communication protocol that can resist collective dephasing noise and collective rotation noise is proposed. In the proposed protocol, the classical sender can safely transmit the secret message to the quantum receiver in a quantum channel containing two types of collective noise. In addition, the classical message authentication code technology is employed in the message transmission stage to ensure the integrity of the secret message and enhance the security of the protocol. It is worth mentioning that both the designed semi-quantum environment and the multi-particle system can be experimentally realized, thereby enhancing the convenience and feasibility of implementing the protocol.</p>