A series of regenerated cellulose/soy protein isolate (SPI) beads (RCSB) were fabricated using an environmentally friendly high-voltage electrostatic technique with cellulose and SPI as the main raw materials and sulfuric acid aqueous solution as the coagulant. The structure and physical properties of RCSB were characterized by optical microscopy, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), solid-state C-13 NMR, water contact angle measurement, and thermogravimetric analysis (TGA). The resultant composite beads were round with nano-sized pores on the surface. The size of the dried beads ranged from 300 to 1500 mm and could be controlled by changing fabrication parameters such as the voltage used and the cellulose/SPI ratio. The FT-IR, XRD, C-13 NMR, and TGA results revealed that strong hydrogen bond interactions formed between cellulose and SPI in the beads during the regeneration process, and that the composite beads had good thermal stability. The surface hydrophilicity of the beads decreased as SPI content increased. The cytotoxicity and biocompatibility of the RCSB were comparatively evaluated by 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay and in vitro cell culture. The MTT assay indicated that RCSB extracts had good cytocompatibility for L929 cells. Furthermore, the cells adhered to the RCSB surface and exhibited high attachment efficiency, further confirming the cytocompatibility of the beads. This work provided a facile, environmentally friendly, and controllable method for the construction of biocompatible cellulose/SPI-based beads with potential application in biomaterials.