Colloidal particles in a nonpolar media are closely correlated to industrial applications in particular particle-based electrophoretic display techniques. However, the synthesis of the commonly used poly(12-hydroxystearic acid)(PHSA)-based stabilizers for the dispersion polymerization of polymer particles in nonpolar solvent are troublesome. We report a sorbitan trioleate (Span 85)-based macromolecular copolymer stabilizer that can be easily synthesized and used for the preparation of PMMA particles in a nonpolar solvent. This is realized by synthesizing random copolymers of methyl methacrylate (MMA) and polymerizable sorbitan trioleate (M-Span 85), and the latter can be synthesized from the commercial product Span 85. Using this stabilizer, the resulting PMMA particles have narrow size distribution and tunable diameters. With the stabilizers, transferring water-dispersible particles to a nonpolar solvent and further preparing core/shell particles was verified to be a useful route. This provides an effective approach for using water-dispersible functional nanoparticles in nonpolar environments. In addition, the prepared PMMA particles are demonstrated to be a useful model system to study crystallization or glass transitions by quantitative confocal microscopy.