An isolongifolenone oxime ether derivative is prepared by the following steps of: taking isolongifolenone as the raw material, synthesizing isolongifolenone oxime through addition-elimination reaction, and performing alkylation reaction of the isolongifolenone oxime. Simultaneously, the isolongifolenone oxime ether derivative disclosed by the invention can inhibit bacteria, such as staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, bacillus proteus vulgaris and pseudomonas aeruginosa, and fungus, such as Aspergillus niger, exserohilum turcicum, corn sheath blight, alternaria musae Bovr.et Bat. and colletotrichum musae; and the isolongifolenone oxime ether derivative has the excellent insecticidal action for insect pests, such as aphid and rice planthopper.