The effects of vibromilling on particle size, crystalline structure, optical density, and the plasticizer absorption of poly(vinyl chloride) (PVC) were studied through Fourier-transform infrared spectroscopy, scanning electron microscopy and physical property tests. The experimental results show that the intensity of the FTIR absorption band at 635 cm−1of PVC becomes weaker and tends to disappear during vibromilling. The particle size of PVC is decreased, and the surface area and the amount of plasticizer absorption increase with increased vibromilling time. The low molecular weight PVC so prepared has lower crystallinity and glass transition temperature, and higher plasticizer absorption capacity; it should have good processability.