A catalyst for water decomposition, a preparation method therefor and use thereof. The catalyst for water decomposition is at least one of Li2MSiO4, Li2MTiO4, Li2MGeO4, Li2MSnO4 or Na2MP2O7 which comprise tetrahedral structures in crystals thereof, M being a transition metal. During the catalytic water decomposition, as Li or Na ions are discharged, the crystal structures are structurally rotated or rearranged, such that hydroxyl groups or water molecules absorbed by two adjacent transition metals on the surfaces of the crystals form short hydrogen bonds. Thus, the potential energy for breaking the hydrogen bonds is reduced and O-H bonds can be broken using lower energy; and the transfer of protons is promoted, such that the protons on the surfaces of the crystals can be transferred more quickly. The catalyst reduces the overpotential during water decomposition and increases the catalytic efficiency by forming a unique low energy barrier and double-center catalytic process on the surfaces of crystals.