Abstract: Numerical analysis of a Yb3+-doped fiber laser pumped by 980nm laser source has been presented in this paper. It has been studied that the relationships between the important characteristics of the Yb3+ doped fiber laser such as threshold power, output power and gain and laser parameters such as pump power, fiber length, mirror reflectivity and Yb3+ concentration. A highly-doped Yb3+ fiber ring laser with short cavity has been presented. Numerical results are coincident with the experiment phenomenon.