To investigate the strong and effective sericin fixing agents and conditions, raw silk fibers were treated with the mixtures of urea-formalin, thiourea-formalin and melamine-formalin as sericin fixing agents, respectively. And the treated raw silk fibers were degummed by the degumming liquors of alkaline detergent and sodium carbonate to confirm the hardness of sericin fixation. The weight of raw silk fibers was decreased in the process of sericin fixation treating at 80$^{circ}C$ for 60min. The effective sericin fixation was obtained by treating at $60{sim}80^{circ}C$ for 15min with the mixture of melamine and formalin. The mixture of melamine and formalin showed an outstanding ability of sericin fixation because the three amino groups of melamine were able to cross-link the hydroxy amino acids of sericin such as serine with the assistance of formalin.