The invention discloses a high-pressure composite 
metal hydride hydrogen storage tank and a 
hydrogen storage method thereof. The 
hydrogen storage tank comprises a base support and a 
hydrogen storage tank shell with an opening in the bottom, and the 
hydrogen storage tank shell is installed on the base support in a sealed and buckled mode. A hydrogen inlet and a hydrogen outlet are formed in the 
hydrogen storage tank shell. A hydrogen storage 
alloy storage space, a 
gaseous hydrogen storage gap and a circulating heat exchange 
system are arranged in the hydrogen 
storage tank shell. The hydrogen storage 
alloy storage space is filled with hydrogen storage 
alloy, and the circulating heat exchange 
system is used for absorbing heat when the hydrogen storage alloy absorbs hydrogen and heating the hydrogen storage alloy when the hydrogen storage alloy releases hydrogen. According to the high-pressure composite 
metal hydride hydrogen storage tank and the hydrogen storage method thereof, a gas hydrogen storage gap is formed in the hydrogen storage tank, the size of a reserved gap can be adjusted according to the requirement of hydrogen storage 
mass density, hydrogen storage of different 
mass densities is achieved, the advantages of high 
mass density of high-pressure gas hydrogen storage and high 
volume density of 
solid hydrogen storage are fully combined, and the volume of the 
solid hydrogen storage part is adjusted, the purpose of storing more hydrogen under equal pressure is achieved.