Taking the effect of industrial workshop’s aspect ratio on indoor temperature distribution as research object,using finite volume numerical method to dispersed solving for mass conservation equation and energy conservation equation.This paper research distribution of streamline and isotherm and variation of Nu in industrial workshop of different aspect ratio with Ra among 10 3~10 6.The results of analysis indicate that when increasing Ra,heat transmission form turns heat conduction into convection heat transfer,the isotherms change from vertical to horizontal gradually.The indoor streamlines form two vortexes around the model boundary,the vortexes are broken up with Ra.It’s separated into two vortexes when B=0.5 or B=1.And it’s separated into three vortexes when B=3 or B=2 with slight turbulent state. Nu increases with the increase of Ra and the related curve presents power exponent.when B=3 Nu is the largest and indicate that the total quantity of heat transfer at most by high temperature wall face cold wall.