The　present　work　reports　a　new　fabrication　method　for　refractory　high-entropy　alloy　(RHEA)　based　on　femtosecond　laser.　The　strengthening　mechanisms　in　ZrNbMoTaW　body　centered　cubic　RHEA　prepared　via　femtosecond　laser　fabricating　are　discussed　comprehensively.　By　analyzing　the　mechanical　properties　of　femtosecond　laser　fabricated　ZrNbMoTaW　RHEAs　with　different　processing　parameters,　the　optimal　femtosecond　laser　fabricating　window　of　ZrNbMoTaW　RHEAs　with　enhanced　microhardness　and　low　porosity　was　obtained.　The　grain　morphology,　phase　structure,　elemental　distribution,　local　misorientation　and　lattice　parameters　of　ZrNbMoTaW　RHEA　at　optimized　processing　parameters　were　investigated.　The　instantaneous　fabricating　temperature　was　measured　to　analyze　the　effect　of　femtosecond　laser　on　powder　melting.　The　results　show　that　the　microstructure　of　ZrNbMoTaW　RHEA　consists　of　homogeneous　BCC1　and　BCC2　phase　distribution　with　refined　grains　(sizeave　=　2.1　μm).　Based　on　the　numerical　deduction　of　RHEA　with　enhanced　hardness,　contributions　to　the　multiple　strengthening　mechanisms　are　given　to　establish　the　relationship　between　the　microstructure　and　hardness　of　femtosecond　laser　fabricating　ZrNbMoTaW　RHEAs,　including　frictional　stress　(16.4%),　dislocation　hardening　(17.9%),　grain　boundary　strengthening　(9.9%)　and　solid　solution　strengthening　(55.8%),　respectively.　Adequate　solid　solution　effect,　high　dislocation　density　and　low　grain　size　endow　ZrNbMoTaW　RHEA　with　high　hardness　(Vickersvalue　=　565.7　HV).　These　suggest　that　femtosecond　laser　is　influential　in　governing　the　mutual　solubility　of　multiple　elements　and　introduction　of　strengthening　factors.　The　revealed　strengthening　mechanisms　can　serve　as　a　basis　for　design　and　the　improvement　of　mechanical　properties　in　NbMoTaW-based　RHEAs.　©　2024　Elsevier　B.V.