The　COVID-19　pandemic　in　China　in　the　winter-spring　of　2019-2020　has　decreased　and　even　stopped　many　human　activities.　This　study　investigates　whether　there　were　any　changes　in　the　water　quality　of　the　Lower　Min　River　(China)　during　the　lockdown　period.　The　time-series　remote　sensing　images　from　November　2019　to　April　2020　was　used　to　examine　the　dynamics　of　the　river＇s　total　suspended　solids　(TSS)　concentrations　in　the　period.　A　new　remote　sensing-based　prototype　was　developed　to　recalibrate　an　existing　algorithm　for　retrieving　TSS　concentrations　in　the　river.　The　Nechad　and　the　Novoa　algorithms　were　used　to　validate　the　recalibrated　algorithm.　The　results　show　that　the　recalibrated　algorithm　is　highly　consistent　with　the　two　algorithms.　All　of　the　three　algorithms　indicate　significant　fluctuation　in　TSS　concentrations　in　the　Lower　Min　River　during　the　study　period.　February　(COVID-19　lockdown　period)　has　witnessed　a　48%　fall　in　TSS　concentration.　The　TSS　in　March-April　showed　a　progressive　and　recovery　back　to　normal　levels　of　pre-COVID-19.　The　spatiotemporal　change　of　TSS　has　worked　as　a　good　indicator　of　human　activities,　which　revealed　that　the　decline　of　TSS　in　the　lockdown　period　was　due　largely　to　the　substantially-reduced　discharges　from　industrial　estates,　densely　populated　city　center,　and　river＇s　shipping.　Remote　sensing　monitoring　of　the　spatiotemporal　changes　of　TSS　helps　understand　important　contributors　to　the　water-quality　changes　in　the　river　and　the　impacts　of　anthropogenic　activities　on　river　systems.