Abstract: A systematic model was developed by combining the procedures of laser kinetics and heat transfer together to explore the radial population density and temperature distribution in the transverse section of a rubidium vapor cell. The relationships between the pump power and the laser output, the optical-optical conversion efficiency and the other relevant physical parameters were obtained. The procedures to improve the pump absorption efficiency were discussed. The influences of the relaxation rate between the two fine-levels 2P3/2 and 2P1/2 on the physical characteristics of a DPAL were also revealed. The results show that: when different uses of diode-pumped alkali metal vapor lasers are designed, it is necessary to consider various factors in order to determine the corresponding optimal structural parameters.