Abstract: Based on the three-level rate equation, a simulation model of the end-pumped K vapor laser threshold was established, and the threshold characteristics of diode pumped K vapor laser was analyzed. The influences of operation parameters on the threshold pumped power intensity were investigated, which was based on this model. The result shows that cell's temperature and length both govern the distribution of populations of K, thus combining to impact on the threshold pumped power intensity, and there exists optimal temperature and length. The threshold power intensity linearly increases with pump linewidth. The buffer gas pressure impacts on the threshold intensity by changing the cell's absorption efficiency of the pumped power. High window transmittance and less than 70% output coupling can make threshold keep in a lower level. The study for various parameters of components will provide reference for the design and optimization of the systems, and diode pumped potassium vapor laser output.