A reaction of terbium chloride hexahydrate and 4-chlorobenzoic acid was used to form a terbium complex on the surface of an alkaline calcium carbonate core. Different concentrations of high-density polyethylene (HDPE) toluene solution were then coated onto the prepared terbium complex/calcium carbonate composite fluorescent material (referred to as Material I), which resulted in a series of core-shell HDPE/terbium complex/calcium composite fluorescent materials (referred to as Material II). The structures of these materials were identified and analyzed using UV spectroscopy, IR spectroscopy, X-ray diffraction, transmission electron microscopy, energy-dispersive X-ray spectroscopy and inductively coupled plasma-optional emission spectrometry. The thermal stability and fluorescence of these materials were also examined, and results showed that both Materials I and II were shown to have high thermal stability and high levels of fluorescence. These new types of composite fluorescent materials not only offer economic savings on expensive rare earth resources through reduced production costs, they also offer an effective alternative method for the preparation of highly fluorescent, highly temperature resistant binary terbium complexes. Further, the use of the polymer polyethylene coating on the fluorescent material significantly enhanced the emission intensity of the composite fluorescent materials and offers new possibilities for the production of high-end rare earth fluorescent materials.