ByusingtheobservationalO3dataofKunmingandHongKongduringtheperiodof1997-2001,thepaperstudiesthedistributionandvariationoftotalozoneinlowlatituderegionofChina.ThestudyshowsthatthecharacteristicsofvariationinKunmingandHongKongareverysimilar,andthetotalozoneinthewesternareasislargerthanintheeasternones.Itismaximuminsummerandminimuminwinter.