A typical Mesozoic (Tertiary) synsedimentary system of evaporate and mudrock occurs in the middle and lower parts of the 4th Member of Shahejie Formation in the Dongying sag, East China. To investigate mineral elements, carbon isotope, and hydrocarbon generation of synsedimentary evaporate and mudstone, an intense sampling for saline section was conducted in two deep wells (well Haoke-1 and well Fengshen-2) in the Dongying Sag. The results show remarkable response differences, characterized with low contents in Al, Mn and Ba, high in Na, Ca and Mg, and abnormally high in Sr; and a distinct response of distribution of feature element ratios, low V/Ni, and(Fe+Al)/(Ca+Mg), and high Sr/Ba, Fe/Mn and Sr/Ca.