In this paper, we study the effects of Pr substitution on the hydrogenating process and magnetocaloric properties of La_(1-x)Pr_xFe_(11.4)Si_(1.6)H_y hydrides. The powder x-ray diffraction patterns of the La_(1-x)Pr_xFe_(11.4)Si_(1.6) and its hydrides show that each of the alloys is crystallized into the single phase of cubic Na Zn_(13)-type structure. There are hydrogen-absorbing plateaus under 0.4938 MPa and 0.4882 MPa in the absorbing curves for the La_(0.8)Pr_(0.2)Fe_(11.4)Si_(1.6) and La_(0.6)Pr_(0.4)Fe_(11.4)Si_(1.6) compounds. The releasing processes lag behind the absorbing process, which is obviously different from the coincidence between absorbing and releasing curves of the La Fe_(11.4)Si_(1.6) compound. The remnant hydrogen content for La_(0.6)Pr_(0.4)Fe_(11.4)Si_(1.6) is significantly more than that for La_(0.8)Pr_(0.2)Fe_(11.4)Si_(1.6) after hydrogen desorption, indicating that more substitutions of Pr for La are beneficial to retaining more hydrogen atoms in the alloys. The values of maximum magnetic entropy change are 14.91 J/kg·K and 17.995 J/kg·K for La_(0.8)Pr_(0.2)Fe_(11.4)Si_(1.6)H_(0.13) and La_(0.6)Pr_(0.4)Fe_(11.4)Si_(1.6)H_(0.87),respectively.
