<p>This study designed a flat plate repeated bending fatigue testing machine based on the opposite-center crank driving mechanism and realized remote control and operation. This testing machine converts the continuous unidirectional rotation motion of the motor into the linear repeated motion of the slider to actuate the specimen. Based on the principle of similar triangles, the amplitude of the specimen can be adjusted by replacing the eccentric sleeve. This study conducted the strength verification of key components and completed mechanical analysis and design of the flat plate based on material mechanics and finite element numerical simulation. The intelligent networked operation and maintenance system of the testing machine was developed by integrating PLC (Programmable Logic Controller), ISPSoft software, HMI (Human Machine Interface), and its accompanying PIStudio engineering platform software. Based on the developed testing machine, two types of metallic materials were subjected to repeated bending fatigue tests under different stress levels, verifying the repeatability of the fatigue tests. The S-N curves were fitted based on the fatigue test results, and SEM (scanning electron microscope) fracture analysis indicated successive surface/subsurface crack initiation and propagation leading to specimen failure.</p>