The research object is indoor natural convection heat transfer under different heat source location,using FVM numerical method to dispersed solving for mass conservation equation and energy conservation equation.Researched distribution of streamline and isotherm and variation of Nu in powerhouse with Ra among 10 3~10 6 when different heat source location.The results of analysis indicate that when Ra=10 3, the isotherms expand outward centring on the heat source and present shapely arcuation.When increasing Ra,isotherm shape changes gradually,thin boundary layers appear on cold wall and hot wall.The streamlines are two symmetrically reverse vortexs.As increasing Ra, the vortexs change in size and move. As Ra=10 3,Nu reaches maximum in the case of D=0. the effect of heat source location on heat transfer quantity is obvious.The curve of Nu is steepest when D=0.5 and smoothest.There is a power relationship between Nu and Ra, the linear correlation fitting 90%.The conclusion provides a theory basis for the research of complex indoor heat transfer mechanism.