Abstract:BC/AuNPs composite films were prepared by in-situ reaction on substrate of BC membrane synthesized by fermentation, which can realize controllable synthesis of AuNPs and preparation of large size composite membrane. Effects of dosage of chloroauric acid and reaction time of in-situ on morphology of BC/AuNPs composite films were studied. Those films were applied in catalytic degradation of p-nitro phenol. The effects of catalyst dosage, dosage of reductant, and environment temperature on reduction of p-nitro phenol were investigated. The results show that AuNPs composite films with uniform size and moderate density can be prepared under the conditions including dosage of 1% gold chloride acid of 1 mL, and in situ reaction time of 2 min. The highest catalytic efficiency is obtained under the conditions including dosage of gold chloride acid of 1.4 g, sodium borohydride of 0.24 mol/L, and temperature of 60 ℃.