Atmospheric chaotic properties over a linuted area are investigated in terms of the EOF approach. Compared to the phase spacecont inuat ion based on time lag drifting,orihogonality of basic vectors in the space is fully, guaranteed by the EOF technique whichovercomes the problem of the drifting continuation that can be done of singlestation data only;This paper presents the EOF decomposition and computation of 1980～1986 ECMWF dailygridded data of Asian 500hPa height with the atmospheric fractual dimensionality D=6.2,suggesting that the chaotic attractor behind the atmospheric system should have a 7D system,i.e, seven variables to describe the system.