The present work aims on heredity effect between the as-cast and annealed microstructure in the La-Mg-Ni based electrode alloys. Experimental and thermodynamic assessments demonstrate a series of solid state phase transformation reactions taking place successively during the annealing process. Phase constitution, grain size and micro-morphology of the as-cast alloys which have significant effect on the kinetics of the phase transition during annealing are considered to be closely related with the annealed microstructure. Appropriate increasing the casting cooling rate leads to fine microstructure and less LaNi5 and (La,Mg)Ni-2, which is more favorable to development of high abundance of (La,Mg)(2)Ni-7 after annealing. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.