The present invention discloses an inclined plane machining tool with an angle adjustable, and belongs to the technical field of machinery manufacturing. The technical problem of clamping and positioning a part when an inclined plane is machined on a lathe or a boring machine is mainly solved. A part installation platform with an angle adjustable is provided, comprising an inclined rotary table (1), an adjusting mechanism (2), a shafting (3), a pedestal (4) and a locking mechanism (5); the inclined rotary table is used for clamping a part having inclined plane characteristics; the pedestal is installed on a workbench of a machine tool via a pressing plate; the adjusting mechanism adjusts an included angle between two adjusting rods via a leading screw and further adjusts a support height, so that the inclined rotary table rotates around the shafting, and inclination adjustment is achieved; the locking mechanism is mainly used for locking a distance between the inclined rotary table and the pedestal, and is characterized in that the height of the locking mechanism is adjustable, and no extra space is occupied; and the shafting is mainly used for supporting the inclined rotary table and indicating the inclination of the inclined plane. The inclined plane machining tool is simple in structure, convenient to operate, and wide in application range.