The dynamics of residues and degradation of pendimethalin in soil and potato shoots in both Anhui provinces and Beijing were investigated in the field.The pesticides were extracted using solvent of acetonitrile,and the pesticides extracted from sample were separated and purified with dispersion solid phase extraction.The pesticides were finally detected by GCMS，quantified with selected ion monitoring (SIM) mode.The average recoveries of pendimethalin were 84.5%～89.8% for potato tuber,91.5%～101% for potato shoots and 78.7%～88.1% for soil,respectively,with relative standard deviation (RSD) of 4.8%～8.5%、6.2%～8.2% and 5.2%～7.8%,respectively,in potato tuber,shoots and soil.A field experiment was a1so conducted to reveal the dynamics of pendimethalin residues in potato shoots and soil in the two provinces．The results showed that the half life of pendimethalin was 21.0 days,30.1 days in soil and 9.5 days，10.6 days in potato shoots in Anhui（fluvo aquic soils） and Beijing （cinnamon soil）respectively.After harvest,the residue of pendimethalin in potato tuber were less than 0.01 mg·kg-1and below EU maximum residue limits of 0.05 mg·kg-1.The results provided reference to understand the residue level of pendimethalin in environment and transformation in the food chains.