This research is aimed at exploring the necessity of shade on the north facade and optimal selection of shading device. Firstly, the direct and diffuse solar radiation distribution on the surface of each orientation is analyzed in the air conditioning period in Shanghai and Xiamen. Secondly, the simulated building model is established to analysis the impact of different external shades on solar radiation heat gain and day-lighting with Energy-plus. These shades include fixed overhang of different dimensions, roller with different properties and louver of different slat angles. The glare index of different shade devices is also analyzed, results show that the hours exceeding the glare index set point of the fixed overhang and roller are far more than louver’s. Finally, the impact of different external shades on lighting energy consumption and air conditioning energy consumption on the north facades is analyzed. Results show that the use of medium-reflect and medium-transmit external roller is the most energy-saving in Shanghai, the effect of adjustable external blind is close to the roller, and the effect of fixed overhang is not obvious. In Xiamen, the use of adjustable external blind is the most energy-saving, the next is roller, and the last is fixed overhang. Taking energy-saving and glare into consideration, adjustable louver is the best choice of shade on the north facade in Shanghai and Xiamen.