Deriving　marine　gravity　is　one　of　the　important　applications　of　satellite　altimetry　in　earth　science.　The　quality　of　marine　gravity　derived　from　each　altimeter　data　always　is　limited　by　the　range　measurement　on　the　certain　ground　track　spacing.　We　assess　the　performance　of　Jason-2/geodetic-mission　(GM)　altimeter　in　deriving　marine　gravity　by　the　improved　range　from　waveform　retracking.　The　singular　value　decomposition　was　applied　to　denoise　waveforms,　and　the　waveform　derivative　retracking　was　employed　to　improve　the　sea　surface　heights　(SSHs).　Finally,　Jason-2/GM-derived　gravity　anomalies　on　1　＇　x　1　＇　grids　were　determined　by　the　least-squares　collocation　method　based　on　the　resample　5　Hz　SSHs　around　the　South　China　Sea　(SCS).　Assessed　by　ship-borne　data　from　different　institutions,　the　accuracy　of　Jason-2/GM-derived　gravity　is　consistent　with　that　of　the　V27.1　and　DTU13　models.　Moreover,　with　the　application　of　waveform　derivative　retracking,　the　accuracy　of　gravity　anomalies　has　improved　from　6.6　mGal　before　retracking　to　5.5　mGal　after　retracking　over　the　open　ocean,　and　from　8.9　to　7.4　mGal　over　the　coastal　area.　It　is　better　than　the　results　obtained　by　traditional　retracking　methods,　including　off-center　of　gravity　(OCOG),　5-beta,　threshold,　Ice-1,　and　maximum　likelihood　estimator-4　(MLE4).　Furthermore,　evaluated　by　V27.1　and　DTU13,　the　result　shows　root　mean　square　(RMS)　difference　of　2.0　mGal　and　3.0　mGal,　respectively.　Therefore,　the　waveform　derivative　retracking　is　an　effective　method　for　altimeter　data,　and　the　accuracy　of　derived　gravity　is　an　improvement　by　retracked　SSHs.