Abstract: Novel 2-acyl cyanoacetic acid derivative SYP-10898 was synthesized by using 1-tert-butyl-4-(chloromethyl)benzene as starting material via four step reactions including cyanation,esterification,ester exchange and acylation,and its structure was confirmed by 1H NMR and elemental analysis.The bioactivity test results at greenhouse showed SYP-10898 has excellent efficacy for adult carmine spider mite (Tetranychus cinnabarinus) with LC50 value of 3.67 mg/L,which is better than that of cyflumetofen.Field trial results also showed that SYP-10898 has excellent quick effect with 93% control 3 days after application,and good persistent effect with 79% control 30 days after application against Panonychus citri at 50 mg/L.