Highly　dynamic　movements　such　as　jumping　are　important　to　improve　the　agility　and　environmental　adaptation　of　humanoid　robots.　This　article　proposes　an　online　optimization　method　to　realize　a　vertical　jump　with　centroidal　angular　momentum　(CAM)　control　and　landing　impact　absorption　for　a　humanoid　robot.　First,　the　robot＇s　center　of　mass　(CoM)　trajectory　is　generated　by　nonlinear　optimization.　Then,　a　quasi-sliding　mode　controller　is　designed　to　ensure　that　the　robot　tracks　the　CoM　trajectory　accurately.　To　avoid　unexpected　spinning　in　the　flight　phase,　a　center-of-pressure-guided　angular　momentum　controller　is　designed　to　stabilize　the　CAM.　The　modifications　of　CoM　and　CAM　are　realized　by　online　optimization　of　dynamic　components　and　inverse　dynamics.　Two　quadratic　programming　optimizations　are　utilized　to　generate　feasible　contact　force/torque　and　joint　acceleration　referring　to　uplevel　CoM　and　CAM　controllers.　In　addition,　a　viscoelastic　model-based　controller　is　designed　to　absorb　the　vibration　caused　by　a　large　contact　impact.　A　simulation　and　experiment　of　a　0.5-m　high　(foot　lifting　distance)　vertical　jump　are　achieved　on　a　humanoid　robot　platform　in　this　article　(Fig.　1).