Abstract: The in-situ tensile, compression and fatigue experiments of materials is an important method to evaluate the mechanical properties of the materials in terms of strength, formability, stiffness and toughness. In view of the demand of the in-suit tests in micro scale, with extremely low-speed and high-precision in-situ tensile tests in recent years, a novel in-situ tensile test system is designed, to realize a maximum tensile pressure of 4500 N and a minimum tension and compression speed of 1 μm/s by the speed closed-loop control. The system is built with various test modes such as the load mode, the displacement mode, and the fatigue mode. Meanwhile, the limit protection and overload protection functions are also available. It can also be used in combination with the SEM or the optical microscope to observe and analyze the microscopic changes of material structures. The measured results show that the system can be well applied in the evaluation of the physical properties and the failure analysis of materials.