A new catalytic kinetic spectrophotometric method for the determination of trace zinc(II) was developed, which is based on the decolour reaction of H2O2 with calcon catalyzed by zinc(II) in weak acid medium. The optimum condition and kinetic property of the reaction were also studied. The detection limit in this method is 0.68 microg x L(-1). The apparent activation energy Ea and the apparent rate constant R are 45.1 kJ x mol(-1) and 5.80 x 10(-3) s(-1) respectively. The range of determination is 0.80-40.00 microg x L(-1). The method has been applied to the determination of zinc(II) in Mongolian medicine and hair sample with satisfactory results.