Abstract: At first,the connotation and the dimension of scale of geographical information are extended to full the need of describing the every aspects of it;and three types of concepts of its scale are defined as: dimensions of scale,kinds of scale,components of scale.The dimension of scale of geographical information is consisted of spatial dimension,temporal dimension and semantic dimension.The classifications of scale of geographical information are of phenomena scale,measure scale and token scale.The components of scale of geographical information are of extension,granularity(resolution) and frequence.At last the transform of scale of geographical information and issue of scale choice are discussed.