Abstract In this paper, the synthetic methods for the preparation of o-hydroxyaryl dialkyl phosphine oxides (I) are introduced. The title compounds with low bulky substituent are synthesized successfully by the reactions of the Grignard reagents with diethyl o- hydroxyarylphosphonates derived from the rearrange-ment of aryl dialkyl phosphates in good yields. The title compounds with high steric hindered alkyl groups can be prepared ...