The　newly　developed　hyperspherical　color　space　(HCS)　fusion　method　is　a　cost-effective　panchromatic　(pan)　sharpening　technique,　but　it　still　suffers　from　local　spectral　distortion　and　insufficient　overall　spatial　details.　This　paper　attempts　to　improve　the　HCS　fusion　method　by　combining　the　spectrum　gain　modulation　and　wavelet　transformation　and　presents　a　novel　fusion　method　called　enhanced　HCS　(EHCS)　to　mitigate　the　mentioned　issue.　This　method　mainly　contains　three　steps.　(1)　The　proposed　method　extracts　the　angular　component　from　multispectral　images　through　hyperspherical　color　transformation　(HCT).　(2)　A　modulated　multispectral　image　is　generated　by　using　the　spectrum　gain　modulation.　Then,　the　spatial　details　of　the　modulated　multispectral　image　are　substituted　with　the　spatial　details　of　the　pan　image　by　multiscale　wavelet　decomposition.　(3)　Finally,　the　angular　component　and　modulated　detail　image　are　integrated　to　achieve　the　fused　image　by　the　inverse　HCT.　To　validate　the　proposed　method,　three　high　spatial　resolution　images,　i.e.,　two　WorldView-2　and　one　QuickBird　datasets,　acquired　at　Fujian,　China,　were　used.　The　comparison　with　HCS　method　was　also　done.　Both　the　visual　and　quantitative　analysis　demonstrate　that　the　EHCS　method　can　significantly　preserve　the　spectral　characteristics　and　enhance　the　spatial　detail　as　well.　(C)　2015　Society　of　Photo-Optical　Instrumentation　Engineers　(SPIE)