The invention discloses a preparation method for a thermoplastic-polyimide-based compound material for a bearing retainer. In the preparation method, thermoplastic polyimide is used as a base material, reinforcement and modification materials are added into the thermoplastic polyimide and comprise aramid fiber pulp fibers, graphite fluoride and teflon, wherein the aramid fiber pulp fibers are subjected to reflux cleaning, the cleaned aramid fiber pulp fibers, the thermoplastic polyimide and the graphite fluoride are subjected to vacuum drying, and then are synthesized into the thermoplastic-polyimide-based compound material; and the thermoplastic-polyimide-based compound material is hot-pressed on a hot press by using a retainer mould so as to form a bearing retainer tubular blank. The thermoplastic-polyimide-based compound material is low in density, small in friction coefficients and low in abrasion loss, and distortion temperature is greater than 270 DEG C; and the bearing retainertubular blank which is obtained through hot pressing is light, reduces the weight of a whole bearing, and improves the rotation speed and operation stability of the bearing, and obviously improves efficiency of a main machine.