The　marine　microalga　Chlamydomonas　sp.　JSC4　is　a　potential　lutein　source　with　high　light　tolerance.　In　this　study,　light　intensity　was　manipulated　to　enhance　cell　growth　and　lutein　production　of　this　microalga.　High　lutein　productivity　(5.08　mg/L/d)　was　achieved　under　high　light　irradiation　of　625　mu　mol/m(2)/s.　Further　increase　in　light　intensity　to　750　mu　mol/m(2)/s　enhanced　the　biomass　productivity　to　1821.5　mg/L/d,　but　led　to　a　decrease　in　lutein　content.　Under　high　light　conditions,　most　carotenoids　and　chlorophyll　contents　decreased,　while　zeaxanthin　and　antheraxanthin　contents　increased.　Inspection　of　gene　expression　profile　shows　that　the　lut1　and　zep　genes,　responsible　for　lutein　synthesis　and　flow　of　zeaxanthin　into　violaxanthin,　respectively,　were　down-regulated,　while　zeaxanthin　biosynthesis　gene　crtZ　was　upregulated　when　the　microalga　was　exposed　to　a　high　light　intensity.　This　is　consistent　with　the　decrease　in　lutein　content　and　increase　in　zeaxanthin　content　under　high　light　exposure.