10 new torpenoid thioethers,such as 6,1O-dimethyl 3-thia-undeoa-5,9-dienoio acid esters(8) and 6,1O-dimethyl 9,1O-epoxy-3-thia-6-undeoenoio acid esters(4) were synthesized by condensation of thioglycolio acid esters with geranyl chloride(1) or 6,7-epoaygeranyl chloride(2).Juvenile hormonal activities of the synthotio compounds to pupae of meal worm(Tenebrio molitor L.) were studied.It has been proved that the activities of the epoxy compounds(4) is higher than those of the olefinio compounds(8).Compounds of type 4 showed moderate morphogenetio effect to meal worm pupae at a dosage of 50 μg/pupa.