Four kinds of extracts from the xylem of C. Camphora, ACQ and camphor were selected to make wood preservatives for laboratory toxicity test of wood preservatives for decay fungus. The results showed that the treated blocks with 4% ACQ and 10% methanol extracts could meet the demand of degree Ⅰ of preservation and showed strong resistance to brown-rot fungus attack. The wood treated with 4% camphor extracts, 10% ethyl acetate extracts, and 10% acetone extracts reached the demand of degree Ⅱ and showed moderate decay resistance. The blocks treated with 10% hot water extracts and untreated samples meet the demand of degree Ⅲ. Through XRD comparison, the author was found that the preservative effects of four extracts are proportional to the degree of crystallinity. Crystallization fields 2θ diffraction angle were ordered from larger to little as 10% hot water extracts＞untreated samples＞10% acetone extracts＞10% methanol extracts＞10% ethyl acetate extracts. According to FTIR analysis, the amount of degraded cellulose and hemicellulose increased with the decline of characteristic absorption peak at 1 374, 1 160, 1 106, 1 056 and 897 cm-1, meaning that the preservative effect of corresponding preservatives were getting worse. The peak height of characterization of lignin is higher compared to the untreated wood. I1 510/I1 738, I1 510/I1 374, I1 510/I1 160 of the treated blocks with 10% methanol extracts and 4% ACQ are the smallest in all the treated blocks, which proved that the degradation ability of brown-rot fungus to the holocellulose is the weakest, and the wood preservative is best.