Abstract: Alanine,serine and silk were used as model chemicals and material to study the mechanism of crosslinking between BTCA and silk fibroin via TG analysis.The study compared the TG curves of BTCA and alanine,serine,silk between 100-(200 ℃,)The data showed that except alanine,BTCA exhibited big weight loss when mixed with serine and silk under normal durable press finishing conditions in the presence of NaHPO_2.For the serine has hydroxyl in the structure while alanine has not,so the data indicate definitely that the main crosslinking during the durable press finishing of silk using BTCA is still the ester link.