Based on comparing the key departments of Chongqing between 1997 and 2002,the results show that,in 1997,the economic mode of Chongqing's economic structure is led by primary industry and secondary industry,that the proportion of the tertiary industry of key departments in economic structure is small,that,in 2002,Chongqing's key economic departments are no longer simple economic structure mode which is led by a few departments and which is aided by a lot of departments,that,especially,the development and enlargement of the tertiary industry make Chongqing become big economic system and become economic and cultural center in west China.Future construction should attach importance to the tertiary industry of Chongqing.