The main objective of this study was to investigate the characteristics changes of connective tissue filtering residue collagen of beef after marinated with three kinds of weak organic acids( lactic acid,acetic acid and citric acid) and NaCl. Beef semitendinosus muscle was marinated at 4 ℃ for 24 h in 2% NaCl solution with 1. 5% weak organic acids. The changes of connective tissue filtering residue collagen contents and SDS-PAGE were detected. The thermal shrinkage temperatures( To: onset temperature; Tp: peak temperature; Te: end temperature) of collagen were analyzed by differential scanning calorimeter( DSC). The results indicated that the connective tissue filtering residue collagen with three weak organic acids alone were lower than combined with NaCl. There were no significant effects of protein concentration in different molecular weight in marinated beef. The thermal stability of beef connective tissue filtering residue collagen was enhanced after marinating.