Pure tin (β-Sn) has attracted significant attention due to its excellent chemical properties and plasticity. It is widely used in many fields as solder material and coating material. Presently, there are relatively few investigations on the grain refinement behavior and strength toughness strengthening mechanism of bulk polycrystalline pure tin during rolling. In this work, the evolution of microstructure and mechanical properties and the grain refinement law of polycrystalline pure tin (99.99%) under different rolling processes are studied, which is expected to lay a theoretical foundation for adjusting and optimizing the strengthening and toughening properties of pure tin. The results show that different rolling processes have obvious effects on the microstructure and properties of pure tin. The process of twin excitation and twin induced recrystallization in the deformation process are realized by regulating the factors of temperature, speed and path in the rolling process, in which the rolling speed is the most important factor. The grain refinement mechanism of rolling process is as follows: 60°<100> deformation twins are induced at the initial stage of deformation, and the twins gradually evolve into recrystallized banded structure and divide and refine grains in the subsequent deformation process. Recrystallized grains and twins usually randomize the texture and therefore weaken the concentrated texture produced by the original coarse grain. Rolling deformation can significantly increase the strength of pure tin. The yield strength and tensile strength in TD direction are significantly higher than that in RD direction under unidirectional rolling.