A physical model of diode-pumped alkali vapor lasers, which combines the rate equations of population densities, the axial differential equations of pump and laser power, the radial differential equation of temperature, is reported in this paper. Taking into account the measured distributions of the pump and laser beam radii and the hypothetical distributions of the intensities, this model not only reproduces the observed peak temperature of 346℃, 480℃ and 696℃, which respectively correspond to pump powers of 50 W, 220 W and 370 W for the lasing condition, but also reproduces the observed peak temperature of 321℃, 414℃ and 609℃ corresponding to the same pump powers for the non-lasing condition. A wide region of heat source density of quenching is observed. For the lasing condition, quenching contributes approximately 85% of the total heat energy, whereas for the no-lasing condition it occupies over 95%, showing that quenching is very important and non-ignorable in temperature calculation.