Abstract: [Objective] Chromaphis juglandicola Kaltenbach is an important pest in the production of walnut.This project aims to find new compounds to control it.[Method]Control effect evaluation of a new aphid alarm pheromone analog 12.5; CAU1204 Microemulsion against Chromaphis juglandicola Kaltenbach was studied by pesticide spraying method.[Result]It was suggested that the spraying of 12.5;CAU1204 Microemulsion was safe to walnut and a significant dosage response was observed in the tested dosage range of 7.5 g·ai / hm2-60 g·ai / hm2, and the efficacy ascended along with the dosage increasing.The best effect was obtained in the dosage of 60 g·ai / hm2, and the effect reached up to 74; after the application of 7 d and 9 d.There were no significant differences between the dosages of 30 g·ai / hm2 and 60 g·ai / hm2.The efficacy was significantly increased by 38.83; in the treatment of combined use of 15 g·ai / hm2 CAU1204 and 45 g·ai / hm2 imidacloprid to compare with the same dosage of single CAU1204 treatment.[Conclusion]The new compound CAU1204 Microemulsion showed fine effect to Chromaphis juglandicola Kaltenbach, and the combined use with imidacloprid can significantly enhance the control effect.