Refractory　high-entropy　alloys　(RHEAs)　are　susceptible　to　phase　transition　at　elevated　temperatures,　inducing　deviation　in　the　phase　constitution　from　the　intended　design　hence　affecting　the　performance　significantly.　Accurate　prediction　of　phase　constitution　and　modulation　of　phase　stability　over　a　broad　temperature　range　is　crucial　to　develop　RHEAs　with　superior　properties.　In　this　study,　thermodynamic　and　first-principles　calculations　were　integrated　to　investigate　the　temperature-dependent　phase　constitution　in　the　CrTaVW　alloy　system.　The　effect　of　V　and　W　atoms　occupation　sites　on　the　stability　of　TaCr2　2　Laves　phase　was　evaluated.　Both　V　or　W　atoms　tend　to　occupy　Cr　sites　in　TaCr2,　2　,　and　V　exhibits　stronger　alloying　ability　than　W　due　to　the　reduced　electronic　density　at　the　Fermi　level.　Moreover,　with　increasing　the　doping　content,　the　V　and　W　exhibit　opposite　influencing　trends　on　the　formation　and　structural　stability　of　TaCr2　2　Laves　phase.　The　Gibbs　free　energies　of　the　Laves　phase　and　solid　solutions　with　variable　compositions　were　obtained,　enabling　predictions　for　the　critical　temperatures　of　the　phase　transitions.　The　predicted　behaviors　of　phase　transitions　were　validated　by　experiments.　This　study　provides　guidance　for　modulating　phase　constitution　and　achieving　desirable　phase　stability　in　RHEAs.