The invention belongs to the technical field of fiber production, and particularly discloses a production technology of polyester staple fibers. A polyester fiber piece is processed by the productiontechnology according to the following steps that S1, the polyester fiber piece is put into a rotary drum to be subjected to high-temperature drying treatment; S2, the polyester fiber piece in the S1 is cut to be fibrous; S3, cut fibrous polyester fibers are sterilized by steam and can become fluffy; S4, the steamed polyester fibers is put into an impurity removal pool of a processing device and soaked for 1-2 hours; S5, after a sealing plate is pulled open, a water pump and a conveying belt are started, and the polyester fibers which are subjected to impurity removal are collected on the conveying belt; and S6, the polyester fibers which enable metal impurities to be removed are heated to be molten, then the follow-up fiber spraying operation, traction and fiber stacking operation are conducted, then the polyester fibers which are subjected to fiber stacking operation are cut, and therefore the polyester staple fibers can be obtained. According to the production technology, the polyester fibers are steamed to be fluffy, then the impurity removal pool is arranged, the metal impurities on the surfaces of the fluffy polyester fibers can be rinsed inside the impurity removal pool, andtherefore the working efficiency is improved.