Beijing　as　the　capital　of　China　releases　massive　air　pollutants　and　experiences　the　worsening　summer　O-3　pollution　recently.　This　study　estimates　Beijing　ozone　precursor　emission,　anthropogenic　VOCs　(AVOCs)　being　325.3　kilotons　in　2010,　231.8　kilotons　in　2013　and　190.7　kilotons　in　2015　and　NOx　being　211.3　kilotons　in　2010,　238.3　kilotons　In　2013　and　166.2　kilotons　in　2015.　Then,　we　conduct　surface　O-3　simulation　based　on　WRF-Chem　through　using　different　precursor　emissions,　to　evaluate　the　influence　of　precursor　control　measures　on　Beijing　O-3.　From　2010　to　2013,　AVOCs　reduction　in　Beijing　would　lead　to　O-3　decrease　in　urban　and　suburban　areas　and　O-3　increase　in　some　parts　of　northern　rural　areas;　while　from　2013　to　2015,　AVOCs　and　NOx　reductions　would　produce　O-3　increase　in　urban　and　northern　suburban　areas　and　O-3　decrease　in　southern　suburban　and　northern　rural　areas.　Overall,　the　synergic　reduction　during　2010-2015　could　effectively　mitigate　summer　O-3　pollution　over　Beijing,　with　daily　maximum　1-h　ozone　(DAM1h　O-3)　reduction　exceeding　3　ppb.　Finally,　based　on　2015　emission　condition,　30%　NOx　and　30%　VOCs　emission　reduction　are　further　simulated　to　study　O-3-NOx-VOCs　sensitivity　over　Beijing.　The　simulated　DAM1h　O-3　reduction　due　to　NOx-　or　VOCs-reduction　shows　that　O-3　is　predominantly　sensitive　to　VOCs　in　urban　and　northern　suburban　Beijing,　but　seems　to　be　control　more　by　the　mixed　chemistry　in　southern　suburban　and　northern　rural　Beijing.　However,　NOx-sensitive　condition　is　never　found　in　rural　Beijing.　The　distribution　of　simulated　H2O2/HNO3　for　the　distinguished　VOCs-　and　NOx-sensitive　grids　shows　that　95th　percentile　for　VOCs-sensitive　distribution　and　5th　percentile　for　the　NOx-sensitive　distribution　are　2.48　and　1.17　in　all　simulated　days.　According　to　the　determined　transition　values,　most　Beijing　is　under　VOCs-sensitive　regime　on　the　condition　of　2015　precursor　emission.