NOVELTY - Insecticidal microemulsion comprises (in wt.%): flubendiamide (0.1-40), pyrethrins (0.2-8), emulsifier (3-19), penetrant (4-13), stabilizer (1-11), co-solvent (2-16) and deionized water (20-69). The emulsifier is selected from nonylphenol polyoxyethylene ether, biphenyl polyoxyethylene ether, calcium dodecylbenzene sulfonate or their mixtures. The penetrant is selected from diethylhexyl sodium sulfosuccinate, organic silicon 810c, azone compound or their mixtures. The stabilizer is butyl glycidyl ether, sodium sorbate, propenyl glycidyl ether or their mixtures.    USE - Insecticidal microemulsion used for preventing and treating Spodoptera litura and Helicoverpa armigera.    ADVANTAGE - The insecticidal microemulsion is eco-friendly and safe to human, poultry and other beneficial organism, does not cause disease easily, and is free from toxic solvent like dimethylbenzene.    DETAILED DESCRIPTION - Insecticidal microemulsion comprises (in wt.%): flubendiamide (0.1-40), pyrethrins (0.2-8), emulsifier (3-19), penetrant (4-13), stabilizer (1-11), co-solvent (2-16) and deionized water (20-69). The emulsifier is selected from nonylphenol polyoxyethylene ether, biphenyl polyoxyethylene ether, calcium dodecylbenzene sulfonate or their mixtures. The penetrant is selected from diethylhexyl sodium sulfosuccinate, organic silicon 810c, azone compound or their mixtures. The stabilizer is butyl glycidyl ether, sodium sorbate, propenyl glycidyl ether or their mixtures. The co-solvent is selected from isoamylol, ethyl acetate, n-butanol or their mixtures. An INDEPENDENT CLAIM is also included for a method for preparing insecticidal microemulsion, which involves:    (A) placing flubendiamide, pyrethrins, emulsifier, penetrant, stabilizer and co-solvent in a high speed shearer;    (B) stirring the mixture to mix ingredients uniformly;    (C) adding deionized water to the mixture with stirring the mixture uniformly;    (D) storing the mixture for 5-12 hours; and    (E) heating the mixture at 46-57 degrees C with stirring uniformly to obtain microemulsion.