Abstract: Proton radiotherapy has gradually become a precision radiotherapy technique owing to the characteristic of Bragg Peak on the depth-dose distribution. This paper introduces the details of three proton beam reference dosimetry methods as well as the corresponding limitations in clinical proton modalities. Further discussions on the correction terms and improvement methods of measurements combined with Monte Carlo techniques have been proposed. Finally, the state-of-the-art determination on microdosimetry of proton beams has been summarized, which provides a reference for research on proton beam water absorption dose measurement.