One dimensional (1-D) and three dimensional (3-D) ZnO were growth by a hydrothermal method. ZnO 1-D was employed as a support for silver nanoparticles in order to design a new catalyst and used on the steam reforming of methanol (SRM) reaction for H2 production. The catalytic activity of the Ag/ZnO sample with low content of Ag showed better performance on the SRM reaction than on high silver loading catalyst. So, the sample with small Ag particle size showed best performance in methanol conversion than catalyst with big Ag particle size, this finding could be attributed to the high ZnO/Ag ratio. According to results of SEM and TEM techniques the catalytic activity: methanol conversion, H2 and low CO production observed on the Ag/ZnO 1-D catalyst occurs in the edge sites rather than the rim sites. The role of Ag is to accept the hydrogen to be released to the gas phase. In addition, the 1.5Ag/ZnO 1-D catalyst showed good stability during the reaction.