Basic lithium phosphate and stoichiometric lithium phosphate were prepared and their catalytic properties were compared. Using basic lithium phosphate as the isomerization catalyst for propylene oxide led to higher selectivity in allyl alcohol and better propylene oxide conversion than stoichiometric lithium phosphate. The fresh and deactivated basic lithium phosphates were also characterized by X-ray diffraction. Results showed that new phases appeared in the deactivated catalyst. An isomerization mechanism for propylene oxide catalyzed by basic lithium phosphate was proposed. Results of temperature programmed desorption of CO2 showed that the surface basicity of the catalysts had a great effect on their catalytic properties and that the catalyst with pH = 12 had two basic centers and its catalytic properties were the best.