The invention discloses a drill collar intermediate-temperature phosphating process and a phosphating device thereof. In order to improve the phosphating quality of screw threads at both ends of a drill collar workpiece, and change current situations of incomplete phosphating pretreatment, incomplete phosphating posttreatment and unstable process appearing in a conventional normal-temperature hand brushing phosphating process, the process of the invention comprises the following steps: degreasing, washing with cold water, washing with an acid, washing with cold water, phosphating, washing with hot water, dewatering, and sealing to coat oil. Eight fixed impregnating tanks of the phosphating device (1) are successively arranged side by side, the fixed impregnating tanks (1) are provided with tank solution heating assemblies (2), water supply devices (6), a tank solution circulation system (5), a waste gas exhaust system (3) and an electronic control system (8); the extension lines of the axes of the fixed impregnating tanks (1) are provided with a fixed bracket (4) and a free bracket (9). The beneficial effects are that: the process is standardized and orderly, operations are simple, the process flow is stable, and the processing quality is greatly improved.