The　Gravity　Recovery　and　Climate　Experiment　(GRACE)　gravity　satellites　can　only　detect　low-resolution　marine　gravity　change.　This　study　proposes　to　use　satellite　altimetry　data　to　construct　high-resolution　marine　gravity　change　rate　(MGCR)　model.　The　marine　gravity　field　change　is　mainly　caused　by　the　seawater　mass　migration.　Based　on　the　spherical　harmonic　function　(SHF)　method　and　mass　loading　theory,　a　spherical　harmonic　synthesis　formula　is　constructed　to　calculate　MGCR.　This　idea　is　utilized　to　establish　MGCR　model　in　Arabian　Sea　(AS).　First,　the　multisatellite　altimeter　data　from　1993　to　2019　are　grouped,　preprocessed,　and　utilized　to　establish　mean　sea-level　models;　then,　the　long-term　altimetry　sea-level　change　rate　(SLCR)　is　estimated.　Second,　the　altimetry　SLCR　subtracts　the　effects　of　Steric　and　Glacial　Isostatic　Adjustment　(GIA)　to　obtain　the　SLCR　model　caused　by　mass　migration　(AS-MM-SLCR).　Finally,　we　perform　spherical　harmonic　analysis　on　AS-MM-SLCR　and　apply　the　spherical　harmonic　synthesis　formula　to　estimate　MGCR　model　on　5′　×　5′　grids　(AS-SHF-MGCR).　AS-SHF-MGCR　has　higher　resolution　than　GRACE-MGCR,　compensating　for　inability　of　GRACE　to　detect　small-scale　marine　gravity　changes;　the　MGCR　mean　of　AS-SHF-MGCR　is　0.13μ　Gal/year,　which　indicates　the　long-term　rising　trend　of　marine　gravity　in　AS.　This　letter　proposes　a　method　for　calculating　the　MGCR　using　satellite　altimetry,　which　offers　a　novel　approach　for　marine　time-varying　gravity　research.　©　2004-2012　IEEE.