We performed an ab initio study using a method named linearized augmented plane wave with a full potential (FP‐LAPW) based on the density functional theory. We predicted the physical properties of Ru2VGexSb1−x (x = 0, 0.5 and 1) Heusler alloys in L21 structure. We computed the magnetic and structural properties using the general gradient approximation. The modified Becke‐Johnson scheme was used to study the electronic structure of these compounds. The obtained results show that the lattice constants and the spin magnetic moments are in favorable agreement compared with theoretical values and experimental data. The computed densities of state (DOSs) of these compounds indicate a half‐metallic behavior with a real gap for the ternary materials, which gives perfect spin polarization, while for the quaternary one, the DOS indicate a nearly half‐metallic character with a pseudogap in the minority spin close to the Fermi level EF.