Abstract: 1-(3-chlorophenyl)-1H-pyrazole-4-carbaldehyde( 4 ) was synthesized with cyclization and Vilsmeier reaction using 1-(3-chlorophenyl)hydrazine hydrochloride( 1 ) and 1,1,3,3-tetrame-thoxypropane ( 2 ) as raw materials.Claisen-Schmidt reaction of ( 4 ) with 1-(3-(trifluoromethyl) phenyl) ethanone( 5 ) afforded substituted arylketenes( 6 ).Then 3-(3-trifluoromethylphenyl)-5-(3-chlorophenyl-1H-pyrazol)-4,5-dihydropyrazole( 7 ) was obtained by cyclization of 6 with hydrazine hydrate from which 15 novel title compounds ( ZJ1-15 ) were synthesized with isocyanates ( 8 ).The structures of the compounds were confirmed by MS and 1H NMR.The preliminary biological activity showed that the mortality ratio of some compounds against Plutella xylstella were 100% at concentration of 500 mg/L.All the compounds possessed no insecticidal activities against Aphimedicaginis,Nilaparvata lugens or Tetranychus cinnabarinus.