The invention belongs to the technical field of reflection mirror packaging and discloses a coated fiber reflection mirror fixing method. The method comprises the steps of setting a quartz packaging element with a through groove, and enabling a groove opening of the through groove to be upward; injecting gel into the through groove to form a first gel layer, wherein an outer side face of the firstgel layer facing the groove opening of the through groove is a supporting plane, so the supporting plane and the groove opening of the through groove are spaced; extending one end of a coated fiber into the through groove, enabling a part of the coated fiber extending into the through groove to extend along a through direction of the through groove, and setting up the coated fiber on the supporting plane; and injecting the gel into the through groove to form a second gel layer, thereby packaging the coated fiber into the through groove by the second gel layer. According to the method, deformation generated by the quartz packaging element when packaging gel carries out thermal expansion and contraction can be released through utilization of an unilateral opening of a through groove.