A patient interface for continuous positive airway pressure (CPAP) therapy, comprising: a cushion assembly, comprising: a shield, having an opening structured on a first end of the cushion assembly and a ring structure projecting from the opening in a direction towards the first end of the cushion assembly; a cylindrical wall, provided to the opening by a plurality of support structures and formed as concentric with the opening, the cylindrical wall projecting in a manner of having different diameters in two opposite directions along an axis of the opening; and a sealing assembly, provided to the shield of the cushion assembly and together form a breathing chamber, the sealing assembly adapted to seal a face of a patient; a headgear assembly, including a plurality of straps for fixing the patient interface in use; an elbow assembly, adapted to be in fluid communication with the cushion assembly, so as to deliver an air flow to airways of the patient when in use; a connecting ring structure, having one end connected to the cushion assembly and one other end non-detachably connected to the elbow assembly; and a headgear secure assembly, adapted to engage with the connecting ring structure, the headgear secure assembly including a plurality of slots adapted to attach to the corresponding straps in use, wherein the headgear secure assembly is not provided with a forehead support. a cushion assembly, comprising: a shield, having an opening structured on a first end of the cushion assembly and a ring structure projecting from the opening in a direction towards the first end of the cushion assembly; a cylindrical wall, provided to the opening by a plurality of support structures and formed as concentric with the opening, the cylindrical wall projecting in a manner of having different diameters in two opposite directions along an axis of the opening; and a sealing assembly, provided to the shield of the cushion assembly and together form a breathing chamber, the sealing assembly adapted to seal a face of a patient; a shield, having an opening structured on a first end of the cushion assembly and a ring structure projecting from the opening in a direction towards the first end of the cushion assembly; a cylindrical wall, provided to the opening by a plurality of support structures and formed as concentric with the opening, the cylindrical wall projecting in a manner of having different diameters in two opposite directions along an axis of the opening; and a sealing assembly, provided to the shield of the cushion assembly and together form a breathing chamber, the sealing assembly adapted to seal a face of a patient; a headgear assembly, including a plurality of straps for fixing the patient interface in use; an elbow assembly, adapted to be in fluid communication with the cushion assembly, so as to deliver an air flow to airways of the patient when in use; a connecting ring structure, having one end connected to the cushion assembly and one other end non-detachably connected to the elbow assembly; and a headgear secure assembly, adapted to engage with the connecting ring structure, the headgear secure assembly including a plurality of slots adapted to attach to the corresponding straps in use, wherein the headgear secure assembly is not provided with a forehead support.