Abstract: To realize communism is the natural tendency of the human society development and is the ultimate target and highest guiding principle of the CPC.However,in every historic period of time,our party has her concrete target——the lowest guiding principle.Being the combiner of the highest and the lowest guiding principles,the CPC must put into mind both the highest ideal and her present-day task,thus driving forward the career of building up our socialist country with Chinese characteristics.