In this study, hydrogen absorption process was analyzed by using a numerical simulation, which included heat transfer, equilibrium pressure, and heat generation from metal hydride. The dimension of the metal hydride cartridge is 50 mm x 60 mm x 5 mm. The cartridge has a serpentine channel in which metal hydride is packed. The author will fabricate a real cartridge made of stainless steel in the future work. The enthalpy and entropy are experimentally obtained from the equilibrium pressures of LmNi4.73Mn0.12Al0.15. The pressure and temperature are 0.5 MPa and 303 K, which are typical absorption condition for this metal hydride. The calculation results show the transient temperature and hydrogen content distribution. Hydrogen are filled and the temperature reaches a steady state in 240 seconds.