The invention belongs to the technical field of rare earth functional materials, and in particular relates to a capacitive type nickel-hydrogen battery spherical hydrogen storing alloy and a preparation method thereof. A spherical product is obtained by coating the outer surfaces of multiple type AB5 hydrogen storing alloys with sub-micron grade magnesium powder under the action of HPMC conductive glue, wherein the HPMC conductive glue comprises a conductive substance, a binding agent and HPMC. The sub-micron grade magnesium powder has the particle granularity D50 being less than or equal to 2 micron and Dmax being less than or equal to 10 micron. The spherical hydrogen storing alloy is prepared by adding the sub-micron grade magnesium powder into the type AB5 hydrogen storing alloys, and performing vacuum heat treatment, acid pickling, washing by pure water, coating by the HPMC conductive glue and spray granulation, the service lifecycle and alloy power of an electrode can be improved, the material machinability is good, the normal-temperature plastic package can be realized, large package can be realized, the production efficiency is greatly improved, the package cost is reduced, and important economic significance is realized.