© 2019 Elsevier B.V. Substitution effects on weak itinerant electron ferromagnetism in Cr-based ternary alloy CrAlGe were investigated. It was found that substitution of Cr by 3d transition metal with more electrons than Cr enhanced the spontaneous magnetization and Curie temperature. In addition, the itinerancy of CrAlGe was suppressed with the increase of electrons. The ferromagnetism of CrAlGe was related to electron number rather than lattice parameters. The origin of change of itinerancy was suggested to be Coulomb force caused by effective nuclear charge.