The invention discloses an injection mould for an upper housing of a car air filter. The injection mould comprises a fixed mould assembly (1), a movable mould assembly (2), a lateral loose core device (3) and an oblique loose core device (4), wherein the fixed mould assembly comprises a fixed mould seat plate (11), a fixed mould plate (12) and a cavity (13); the movable mould assembly comprises a movable mould seat plate (21), a movable mould supporting plate (22), a movable mould plate (23), a cavity (24) and a mould pushing device (25); the lateral loose core device comprises a telescopic push-pull mechanism (31), a mounting plate (32) and a lateral loose core (24); the oblique loose core device comprises a wedge-shaped supporting plate (41), a supporting baffle (42), a traction mechanism (43) and an oblique loose core (44). According to the injection mould, mutually staggered plastic parts along the loose cores can be conveniently manufactured and repaired, easily damaged parts can be conveniently replaced, the service life of the mould can be prolonged, the precision of the plastic parts can be guaranteed, and the maintenance expense of the mould can be reduced.