Abstract: Based on the color reaction between 2-(2-Quinolylazo)-1,5-diaminobenzene (QADAB) and palladium(Ⅱ),and its solid-phase extraction on the small column packed with the MCI-GEL reverse phase fine separation filler,a new method of photometric determination of trace amounts of Pd(Ⅱ) was proposed.In an acidic medium of 0.2-3.0 mol·L-1 HClO4 and in the presence of CTMAB,a stable coordination complex of QADAB and Pd(Ⅱ) with mole ratio (R∶Pd) of 2 to 1 was formed,which was extracted and enriched on the RP-SPE column,and then eluted with acetone.The absorbance of the color complex in acetone solution was measured at its absorption maxima of 600 nm,with its molar absorptivity of (ε600) 9.63×104L·mol-1·cm-1.Beer′s law was held in the range of 0.01 to 1.5 mg·L-1 of Pd(Ⅱ).In its application to the analysis of some substantial samples,values of recovery found were in the range of 86%-96%.