A method of establishing experimental models of mic row ave radiometric characteristics for extended targets is introduced in this paper . Microwave radiometric characteristics are represented by brightness temperatur e. A large amount of antenna temperature data is obtained through the repeated m easurement of the targets under different conditions and at different time. Appa rent temperature is obtained from antenna temperature through the inversion of t he integral equation. The brightness temperature is obtained from apparent tempe rature by eliminating the scattered radiometric temperature. The formula of brig htness temperature for the targets with respect to incident angle and surface ph ysical temperature are established through two

d

imensional curve

f

itting of brig htness temperature. Comparing the experimental model established by this method with the semi

e

mpirical formula （theoretical model） of water brightness temperat ure

it is found that they are very close in the range of surface temperature （4 \

3

5℃） covered by the measurement and measuring angle 20°\

6

5°. The experimen tal models established with this method for concrete road

asphalt road

and cru shed stone road are also presented.