The invention relates to the field of machining, in particular to a method for machining a stainless steel deep-hole thin-wall part. The method comprises the following steps that a proper blank material is selected, annealing treatment is carried out, and the cutting machining performance of the material is improved; rough turning is carried out, wherein working allowance of a blank is removed, and a workpiece inner hole is machined in dedicated equipment through a corresponding deep hole inner ejector drill; heat treatment and quenching are carried out; the appearance of a workpiece is clamped, and the end faces of the workpiece are turned; lead hole turning and chamfering are carried out; pull-boring and pull-hinging are carried out, the number of times of pull-boring and pull-hinging can be determined according to the working allowance, the number is generally two to four, pull-boring is carried out two times on a dedicated deep hole drilling and boring machine according to the characteristic of the part, after pull-boring is carried out once, the inner hole is machined with certain working allowance reserved, the inner hole is machined to the required size finally, and cooling lubricating oil is adopted in the machining process. According to the method, the precision requirement of the workpiece can be guaranteed, quality is stable and reliable, machining difficulty can be reduced, production efficiency can be improved, and the labor intensity of workers can be reduced.