This paper explored the extraction and determination methods of pentachlorophenol (PCP) in wood package. Pentachlorophenol in wood package was extracted by ultrasonic extraction with methanol using tribromophenol as internal standard, acetylated by acetic anhydride, and finally detected by gas chromatography with electron capture detector. This method showed good linear relationship in 1~20.0 μ g/L, the correlation coefficient was 0.9982. The average recovery ranged from 83.2% to 106.3%, the relative standard deviation was blow 5.32%， the detection of limit of this method was 0.01 mg/kg. Totally 50 wood package samples were detected using this method, and 22% of samples were positive for PCP. The developed analytical method was rapid and accurate, and suitable for the determination of pentachlorophenol in wood package.