Thulium-doped fiber lasers (TDFLs) have been applied in extensive areas, such as medical treatment, plastic welding, lidar, and optical-parameter-oscillation (OPO). In this paper, the research progress of Tm 3+-doped silica fibers and high power TDFLs is presented and the bottlenecks of TDFLs are discussed and analyzed. Adjustments and optimization are promoted from three aspects including fiber design, laser structure and pump approach, and high power TDFLs will be achieved by improving thermal management and non-linear effect.