A facile Solution route was proposed for the successful synthesis of uniform poly(o-phenylenediamine) (PoPD) submicrospheres with all average diameter of 700 nm. Utilizing the reactivity of dedoped PoPD submicrospheres for gold salt HAuCl4, gold nanoparticles can be synthesized in the presence of PoPD without additional reductant For HAuCl4. Furthermore, PoPD submicrospheres with abundant amino groups and pi electrons in benzene rings on their surfaces can significantly stabilize gold nanoparticles, which will lead to the formation of PoPD submicrosphere-supported gold nanoparticles. Reaction conditions, such its addition of poly(vinylpyrrolidone) and concentration of HAuCl4, were found to affect the size of gold nanoparticles. Products were characterized by Fourier-transform infrared (FT-IR) and X-ray diffraction (XRD) spectroscopies. The synthesized PoPD submicrosphere-supported gold nanoparticles with different size were used to evaluate their catalytic performances for benzyl alcohol. Results revealed that PoPD submicrosphere-supported gold nanoparticles showed high yield and selectivity for benzyl alcohol to aldehyde conducted under air and ill water media. The factors, such as catalyst size and amount, solvent, temperature, alkali type, and reaction time, were all systematically investigated to elucidate their effects on the yield and selectivity of catalytic benzyl alcohol reactions.