The invention discloses a cutting saw for a proximal surface sheet of fixed partial denture and a processing method of the cutting saw. The cutting saw is of a toothed structure; the width of teeth is 10mu m, the apex angle of the teeth is 30 to 60 degrees, the total length of the saw is 50 to 150mm, the width of the saw is 2 to 10mm, and thickness of the saw is 30 to 100mu m; during processing, a cleaned stainless steel sheet is putted on a laser cutting machine by adopting a laser cutting method, and parameters of the laser cutting machine are adjusted for micro processing; during use, the current of a laser power supply is 10 to 20A, and the scribing speed is 1 to 3mm/s; finally, edges are deburred and cleaned again. The cutting saw disclosed by the invention can be used for quickly removing a residual bonding agent of the proximal surface of the teeth and polishing the surface; compared with other cutting saws for the proximal surface, the process disclosed by the invention has the advantages of high microprocessing precision, excellent processing speed, higher rate of finished product and good removing effect on the proximal surface; the product can be repeatedly used, the working efficiency can be improved, and the use cost is reduced.