Photodissociation spectroscopy of temperature-controlled hydrated calcium ion, Ca+(H2O), is carried out to investigate the temperature effect on microscopic hydration process of metal ions. The temperature of Ca+(H2O) is controlled by multiple collisions with He gas in the temperature-variable 22-pole ion trap. The temperature of the ion is determined by the rotational analysis of the spectra. The rotational temperature of the ion is confirmed to be well controlled from 30 K to 300 K in the present experiment. The rotational-level dependent predissociation in the 2 B-2(1) state through the states correlating to the Ca+(D-2)+H2O dissociation limit is also discussed. (C) 2011 Elsevier B. V. All rights reserved.