Objective To study on the type of water in Scutellarin and the method of measuring water content. Methods Investigate the type of water in Scutllarin with TGA， DSC and temperature controlled XRPD. Compare three measurements of water， which are LOD（RT， 2. 67 kPa）， LOD（60 ℃， 2. 67 kPa）and Karl Fischer method. Results There were two-molecule crystal water and a little of absorption water in Scutellarin. The Karl Fischer method is better than the other two methods for the measurement of water content in Scutellarin. Conclusion Scutellarin was a dihydrate. If being dehydrated by heating up， it will regain the crystal water and become dihydrate when exposed in humid environment under room temperature.