Abstract: Abstract:Seasonal movements are often large enough that they mask other characteristics of the data that are of interest to analysts of current economic trends. Nowadays seasonally adjustment data are one of the main sources of information used by politicians, economists and business analysts in developed countries. But there are lack of study and practices on seasonal adjustment in china. The article provides an overview of recent development in seasonal adjustment study and practices in the word, and analyzing the problems of seasonal adjustment in china. At last put forward my suggestion that we should develop seasonal adjustment of china in the future