Structural　geometry　constraints,　such　as　perpendicularity,　parallelism　and　coplanarity,　are　widely　existing　in　man-made　scene,　especially　in　Manhattan　scene.　By　fully　exploiting　these　structural　properties,　we　propose　a　monocular　visual-inertial　odometry　(VIO)　using　point　and　line　features　with　structural　constraints.　First,　a　coarse-to-fine　vanishing　points　estimation　method　with　line　segment　consistency　verification　is　presented　to　classify　lines　into　structural　and　non-structural　lines　accurately　with　less　computation　cost.　Then,　to　get　precise　estimation　of　camera　pose　and　the　position　of　3D　landmarks,　a　cost　function　which　combines　structural　line　constraints　with　feature　reprojection　residual　and　inertial　measurement　unit　residual　is　minimized　under　a　sliding　window　framework.　For　geometric　representation　of　lines,　Plucker　coordinates　and　orthonormal　representation　are　utilized　for　3D　line　transformation　and　non-linear　optimization　respectively.　Sufficient　evaluations　are　conducted　using　two　public　datasets　to　verify　that　the　proposed　system　can　effectively　enhance　the　localization　accuracy　and　robustness　than　other　existing　state-of-the-art　VIO　systems　with　acceptable　time　consumption.