��������ң��Ӱ������ (TM��ETM��WFV2) �Գ��н��������е��飬�о� 1990 �����������е���չ����������ͳ��������ϣ��Գ����г�����������Ч�ʽ����о����������: 1990—2013 �곤���н�����������������ӣ�����������֮�⣬����������չ����; �����еķ�չ��ʽ���ⲿ�������ڲ���䷢չ������У����ҳ��н�������״�򵥣����������ܳ��й滮Ӱ��ϴ󣬳�����������ķ���չ�������ڳ�����������Ч�ʵ����; 1990—2012 �������������Ч�����в�������������������ơ�

On the basis of the remote sensing image (TM��ETM��WFV2) of four periods�� the author investi- gated the urban expansion and studied the urban land use efficiency of Changchun City since 1990��combining with statistical yearbook data�� The results showed that the urban built- up area continued to increase from 1990 to 2013 and expanded to all directions except the northeast direction�� The development of Changchun City alternated exter- nal expansion and internal filling and the shape of the city was simple�� The land use was influenced by urban plan- ning obviously and the city developed in an orderly way��which was beneficial to the improvement of the urban land use efficiency�� The urban land use efficiency showed fluctuation but the trend was upward overall from 1990 to 2012��