A phased array antenna includes a phase shifter unit, a waveguide unit and a connection unit, the phase shifter unit has two substrate surfaces and includes at least one phase shifter having two feeding regions; a side where at least one of the substrate surfaces is located is provided with the waveguide unit having a waveguide cavity corresponding to at least one of the feeding regions of each phase shifter; the connection unit corresponds to each waveguide unit and includes an insulation body, the insulation body is fixedly connected with the substrate surface and the waveguide unit on the same side as the insulation body; the insulation body has a first hollow-out portion, the waveguide unit contacts the substrate surface through the first hollow-out portion, a first port of the waveguide cavity is located on a contact surface of the waveguide unit in the first hollow-out portion.