Abstract: Along with development of urbanization,urban thermal field(or urban thermal environment) is changing accordingly as function of numerous factors.One of the changes is the so-called urban heat island effect.To analyze geographical information related to urban land-use types in Macau and to extract data on urban surface temperature as well as urban impermeable surface,GIS and RS were used.Based on the Landsat TM data collected on October 19,2004,factors influencing urban thermal field were studied by the principal component regression method.Results show that the urban thermal field in Macau was greatly affected by impervious surface index,and surface temperature was positively correlated with impervious surface index and road density(P<0.05),while negatively correlated with vegetation index,vegetation cover and proportion of waterbody(P<0.05).