The foreign development of the earth observation technology is briefly introduced. The development trend of the earth observation technology is described from the angle of nation security. Besides, the shortage of the earth observation system in our country is explained on the base of the discussion on the development actuality of the earth observation technology in China. The revelation and suggestion is brought forward. The earth observation system's effect is more and more important on the economy building and technology development, which faces the different requirements on information of the land,the ocean and the atmosphere.