The economic reform launched in 1978 has changed the pattern of social stratification in China. During the three decades since then，newly emerged mechanisms and routes for social mobility gradually replaced the former ones. Consequently，the new pattern of social mobility of the post-reform era becomes sharply differed from that of the pre-reform era. Based on the data gathered from a nation-wide survey conducted in 2001，this paper compares and discusses the differences between the patterns，mechanisms，barriers，and pathways of upward social mobility in pre- and post-reform era. It concludes that the opportunities and pathways for upward mobility，which were solely dominated by government policies during the pre-reform era，have now become increasingly ruled by market mechanism.