A novel method (dynamic water transfer based water activity analyzer 13 (DWT) method) based on Fick's law of diffusion for the accurate measurement of 14 moisture sorption isotherm (MSI) has been developed, and was compared with 15 saturated salt solutions (SSS) method and dynamic vapor sorption (DVS) method. 16 MSIs at 25°C of sultana raisins obtained by the three methods were analyzed and 17 compared, and four adsorption models (BET, Halsey, GAB, and Peleg) were used to 18 fit the results. The MSI curves obtained by the three methods all showed the similar 19 type-Ⅲ isotherm characteristic, but equilibrium moisture content at the same relative 20 humidity (RH) showed some differences, and the repeatability and accuracy were 21 different. Generally, results obtained by the SSS method may have relatively low 22 accuracy due to the relatively high measurement error; results obtained by the DVS 23 Manuscript Click here to access/download;Manuscript;manuscript.doc Click here to view linked References method may lack representativeness due to the small sample size; results obtained by 24 the DWT method may have high representativeness and accuracy at the same time. 25 The fitting results of adsorption models indicated that MSI results obtained by the 26 DWT method had the highest fitting degree with Peleg model. This study may 27 contribute to deepened understandings on MSI measurement of semi-dried foods.