5,5-Dimethyl-1,3,2-dioxa phosphorocyclohexane 2-phosphoryl thioureas (4a-1) were synthesized by the reaction of phosphorus oxychloride with 2,2-dimethylpropanediol, potassium isothiocyanate, and substituted arylamines successively. IR, 1H-NMR and elementary analysis characterized their structures. The antibacterial test showed they were efficient against Fusarium oxysporium and Rhizatonia solani.