Abstract: By means of ³¹P NMR Spectroscopy, the configuration, association, hy-drolic stability and deuterium exchange for dialkyl phosphonates have been studied The ³¹P NMR data show that the dialkyl phosphonates exist in phosphonate form and not phosphite form In presence of silicon compounds, the dialkyl phosphonates have indicated equilibrium between phosphonate and phosphite forms. Associates occur in dialkyl phosphonates by various extent Dialkyl phosphonates hydrolyze easily, the hydrogen on the phosphorus atom is readily exchanged by deuterium in D20 and seperated signals are observed.