The invention relates to an antimicrobial and absorbable suture line and a preparation method thereof. The suture line is made from glycolide, lactide, calcium stearate and chlorhexidine gluconate and has good tensile strength and antibacterial properties. The preparation method includes the following steps that firstly, the glycolide (GA) and the lactide (LA) are put in a reaction kettle in a certain proportion, a catalyst and an initiator are added, vacuumizing is performed, and ring opening polymerization is performed under a stirring condition to generate poly (l-lactide-co-glycolide) (PGLA); secondly, synthesized PGLA is spun on a small home-made spinning machine; thirdly, coating and drug carrying are conducted on PGLA silk threads with a calcium stearate coating solution and a chlorhexidine gluconate solution; finally, the PGLA silk threads are stranded and knitted to prepare the antimicrobial and absorbable suture line. The preparation method is simple and low in production cost, and mechanized large-scale production can be achieved. The prepared antimicrobial and absorbable suture line has good antibacterial properties and can meet the wound operation suture and antimicrobial demand.