Abstract:The optimum ustrasonic-assisted extraction technology of three limonoids constituents from citrus seed was investigated.According to the results of single factor test，the response surface method was used to optimize the extraction process.The optimum test conditions were as follow：the best solvent system was methanol，extraction time 40 min，temperature 33 ℃，and liquid-solid ratio 13 ∶1（mL/g）.In verification test，the extraction yield of three limonoids constituents in citrus seed was 11.804 5 mg/g，basically consistent with the total rate of predicted value was 11.756 9 mg/g.The response surface method was feasible to optimize the extraction technology of limonin，nomilin and obacunone in citrus seed.