The strain generated in a reaction tank of hydrogen storage alloys were measured in order to analyze strain variation in different locations during hydrogen absorption-desorption cycles. Strain gauges were set on the various locations of the tank. The change of strain was continuously monitored using the strain analyzer. The results indicate that plastic deformation had occurred during activation period, and it did not become larger in the later hydriding-dehydriding cycles though the tank still had the ability for elastic deformation. The stress induced by alloy swell on the tank was over 8 MPa. Tangential strain was greater than longitudinal strain in each place. There wasn't much more difference in Longitudinal at respective points while tangential strain in the middle part was much larger than that in two sides' parts of the tank. The nonuniform packing density lead the deformation tended to occur more serious in tail part than in head part. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.