Ph2NH and PCl3 interacted at a molar ratio of 1∶1.05 and slow-elevated temperature and then at 210-220 ℃ for 6 h. The brown solution obtained was treated with H2O to produce a very hard brown solid believed to be a mixture of 5,10-dihydrophenophosphazine 10-oxide(1a) and 10,10(5H,5H)-spirobipenophosphazinium chloride(1b). This brown solid was directly oxidized with peracetic acid in HOAc prior to the separation of them to give compound 10-hydroxy-5,10-dihydropheno-phosphazine 10-oxide(2) with a higher yield(45%) than that of the literature(27%). When treated with excess SOCl2, compound 2 could quantitatively be converted to the corresponding phosphinyl chloride and the latter could further be transformed into 10-methoxy-5,10-dihydrophenophosphazine 10-oxide in 70% as treated with NaOMe in methanol. Compound 2 could also be converted to a bisanion when treated with NaH in DMF. The resulted bisanion reacted with MeI to give 5-methyl-10-hydroxy-5,10-dihydrophenophosphazine 10-oxide in a 73% yield which would be converted to 5-methyl-10-methoxy-5,10-dihydrophenophosphazine 10-oxide in a 56% yield by the same way of synthesizing 10-methoxy-5,10-dihydrophenophosphazine 10-oxide. All these compounds obtained were identified by surveying their melting points, and spectra and elemental analysis.