The invention belongs to the pesticide technology field, and relates to a synergy composition for matrine and tetronic acid pesticides. The mass ratio of matrine to tetronic acid is 50:1-1:50. The matrine in the composition comprises matrine, oxymatrine and a mixture of matrine and oxymatrine, or a series alkaloid extract and its preparation obtained from plants such as radix sophorae flavescentis, Sophora alopecuroides and Subprostrate Sophora Root. The tetronic acid pesticide can be one of spirotetramat, spirodiclofen and spirotetramat or its combination. The composition of the invention is capable of generating cooperation and synergy effects, overcoming harmful biological drug resistance, prolonging the service life of the pesticide, and enlarging the prevention and cure scope, can be used for preventing and treating a plurality of insect diseases on agriculture and gardening crops, especially suitable for insects possessing drug resistance on single pesticide, such as aphid, scale insect, leaf mites, leafhopper, planthopper or whitefly and thrips.