Marine　microalgae　has　great　potential　for　lutein　production　with　the　advantage　of　saving　fresh　water　resource.　Thus,　marine　microalga　Chlamydomonas　sp.　JSC4　is　investigated　as　a　potential　lutein　producer　in　this　study.　The　medium　types,　nitrate-N　and　sea　salt　concentration　are　individually　investigated　to　promote　the　cell　growth　rate　and　lutein　production　of　JSC4.　In　Modified　Bold　Basal　3N　medium,　cell　growth　and　lutein　content　are　optimal　at　the　nitrate-N　concentration　of　1000　mg　L−1　and　sea　salt　concentration　of　2%.　In　addition,　an　innovative　salinity-gradient　strategy　is　operated　to　dramatically　enhance　biomass　productivity　(560　mg/L/d)　and　lutein　content　(3.42　mg　g−1),　resulting　in　the　optimal　lutein　productivity　(1.92　mg/L/d).　Overall,　this　study　clearly　demonstrates　that　salinity　is　a　significant　inducer　of　lutein　accumulation　by　strain　JSC4　and　that　lutein　production　can　be　successfully　optimized　using　the　salinity-gradient　strategy,　which　is　beneficial　for　the　outdoor　large-scale　lutein　production　in　the　future.　©　2019　WILEY-VCH　Verlag　GmbH　&　Co.　KGaA,　Weinheim