Abstract: A new chromogenic reagent 5-(5-fluoro-2-pyridylazo)-2,4-diaminotoluene（5-F-PADAT） has been synthesized and characterized by infred spectometry and elemental analyzer. The chromogenic reaction of 5-F-PADAT with palladium (Ⅱ) was also studied. The experimental results show that Pd(Ⅱ) reacts with 5-F-PADAT to form a stable violetred complex in a solution of 0.32～3.84 mol/L HClO4. The molar ratio of Pd (Ⅱ) to 5-F-PADAT is 1∶1 with apparent molar absorptivity of 4.84×104 L·mol-1·cm-1 at the maximum absorption of 566 nm. Beer′s law is obeyed in the range of 0～2000 μg/L for palladium. The method provides high selectivity and most common ions do not interfere with the determination of Pd (Ⅱ). The method has been successfully applied to the determination of micro-amount of palladium in ore and catalyst samples. The results are in agreement with those obtained by atomic absorption spectrometry.