The　rapid　development　of　Ce-based　magnets　has　promoted　the　utilization　of　rare　earth　(RE)　resources,　yet　the　performance　of　Ce-based　magnets　is　often　undermined　due　to　the　easy　formation　of　CeFe2　phase　with　a　cubic　MgCu2-type　structure.　In　order　to　eliminate　the　CeFe2　phase,　the　La　substitution　on　Ce　in　(LaxCe1-x)(33)Fe66B　(x　=　0,0.1,0.2,0.3,0.4,0.5)　alloys　is　performed　in　this　paper.　It　is　found　that　partial　replacement　of　Ce　by　La　suppresses　the　emergence　of　the　CeFe2　laves　phase　and　promotes　the　formation　of　(La,　Ce)(2)Fe14B　phase.　The　inhibition　mechanism　is　ascribed　to　the　reduced　phase　stability　of　(Ce,　La)Fe-2　phase　due　to　the　partial　replacement　Ce　by　La,　which　is　confirmed　by　our　experiments　and　DFT　(density　functional　theory)　calculation　results.　Moreover,　the　La　atom　is　prone　to　enter　the　lattice　of　(La,　Ce)(2)Fe14B　phase　and　expands　the　unit　cell.　Both　the　Curie　temperature　(T-c)　and　the　saturation　magnetization　(M-s)　of　the　alloy　show　a　noticeable　improvement　because　of　this　volume　effect,　which　is　consistent　with　our　DFT　calculations.