Abstract: This paper presents the trends and characteristics of upper ozone layers over middle latitudes by the analyses of the Umkehr data of the period of 1965~ 1993. The results, from 1965 to 1993, show that the upper ozone variation of middle latitudes per decade are about –1~2%, and the ozone seasonal variations between the layer of 28~36 km and the layer of above 36 km have opposite phases. Because of the eruption of El Chichon and Pinatubo, during the period of 1982~ 1983 and after 1991 there was a sudden change in upper layer.