According to mass balance analysis and their geochemical compositions, the mass transfer and element mobility during regional metamorphism of the pelites of the Shuangqiaoshan Group in the Lushan region are discussed. The results show that the total mass loss values, estimated relative to the low - grade slate using Ti as the immobile reference element, are around 17 % and 23% for the biotite schist and (staurolite) -garnet schist, respectively. The elements Si, Na, K, Rb and Sr have significant mobility while Al, U, REEs etc. are mobile to some degrees during regional metamorphism of the pelites of the Shuangqiaoshan Group. The mass change and the mobility of some elements in question result from the effects of metamorphic fluids on the rocks during the regional metarnorphism.