Pesticides are designated mixture of substances for extenuating and destroying any group of pests such as insects and vegetation. Pymetrozine [6-methyl-4-[(E)-pyridin-3-ylmethylideneamino]-2, 5-dihydro-1, 2, 4-triazin-3-one] is a pyridine azomethine compound which represents a class of insecticide. A Spectrophotometric method has been developed on the modified Fujiwara reaction for the determination of pymetrozine. Pymetrozine directly reacts with chloroform the 45-500C turns out the violet color in the formation of Schiff’s Base (Glutaconic Aldehyde). In the present reaction, the violet color obtained is discharged with a few drops of acetic acid followed by the addition of p- nitro aniline reagent which gives yellow color dyes. The absorption maxima of yellow-colored dye measured at 430 nm. Beer’s law is obeyed over the range of 1 to 10 µg per 10 ml of pymetrozine. The molar absorptivity of the colored system is 1.38×105 L mol-1 and Sandall’s sensitivity is 1.0×10-3µg cm-2. This method is free from the interference of other interfering and can be successfully applied for the determination of various ecological samples.