Abstract: Multiwall carbon nano-bubes (MWCNT′s) was used as adsorbent in the solid phase extraction (SPE) for enrichment of residual triadimefon in water sample, and the enriched analyte was determined by HPLC. A definite volume of water sample was taken and passed through SPE column packed with MWCNT′s at a flow-rate of 4 mL·min-1. Dichloromethane was used as eluant to desorb triadimefon from the column, and the eluate obtained was evaporate to dryness by N2-blowing. The residue was dissolved and made up to 1.0 mL with the mobile phase. Chromatographic separation was made by using C18-column as stationary phase and mixture of CH3OH-H2O (70+30) as mobile phase. Linear relationship between values of peak area and mass concentration of triadimefon was obtained in the range of 1.0~50.0 μg·L-1, with detection limit (3S/N) of 0.3 μg·L-1. Recovery was tested at 2 concentration levels, giving results of recovery ranged from 95.0% to 104%.