Synthetic Aperture Radar （SAR）

as a kind of active remote sensors

is a system that can scan and image earth surface objects in a high resoution using its EM wave. Ever since the late of 1970s

SAR as a way of earth observation has progressed to the space borne stage. However

to utilize SAR image product adequately and efficiently

we often need to locate accurately an arbitrary pixel

which is corresponding with the target on the earth surface. Taking Radarsat 1 as an example

this paper first briefly describes the multi level

multi type traits as well as the product format of SAR image. After comparison of several location methods of remote sensing image

R D theory is proved to have its advantage as the footstone of absolute pixel location model of SAR image. In developing pixel location model

the dilemma of employing direct coordinates transformation is pointed out and two practical location algorithms based on R D theory are presented. The test results betrary that the relative position location algorithm can achieve a high accuracy no less than the similar research till to now in the world. The iteration location algorithm can also achieve a high accuracy permitted in the technical document of RSI Co. and therefore has a certain practicability.