This paper addresses some issues related to relationship between lithospheric thermal regime and depth extent of seismicity. Thickness of seismogenic crustal layer correlates with surface heat flow in most intraplate seismic areas of the world. Although inverse relationship between heat flow and the base of seismogenic zone is obvious, quantitative relationships are less certain. Compilation of previous studies shows that temperatures at the base of seismogenic zone appear to be distributed from about 250° to 450° over a large depth interval, 5-30 km, at different tectonic settings. It supports that temperature is one of factors governing the focal depth. Variations in lithology, slip rate, pore pressure, and focal mechanism may account for the temperature difference. Geothermal gradient data and bottom depth of magnetized layers are also useful proxy to reveal the base of seismogenic zone. These multidisciplinary data may provide a useful indicator of lithospheric thermal structure and improve the correlation with depth limit of seismicity.