The invention proposes a planar waveguide continue transverse stub (CTS) antenna broadband feeding line source based on a planar dielectric lens, which is used for solving the problems of incapability in simultaneously achieving miniaturization, broadband and favorable matching and high difficulty in processing assembly of the traditional line source. The feeding line source comprises an H-surface trumpet (1), a planar dielectric lens (2) and a planar waveguide (3), wherein an output port of the H-surface trumpet (1) is connected with the planar waveguide (3), the planar dielectric lens (2) is arranged in the planar waveguide (3) and comprises an intermediate layer (21) and two matching layers (22), the two matching layers are symmetric to the intermediate layer (21) and comprise a plurality of matching sub layers, each layer adopts a straight line array structure formed by a plurality of strips with different dielectric constants and extend from the middle of the strip straight line array to the two ends, and the dielectric constants of the strips are gradually reduced. The planar waveguide CTS antenna broadband feeding line source has the advantages of small structural size, wide frequency band and favorable matching performance, is easy to produce, adjust and assemble, and can be applicable for planar waveguide CTS antenna feeding.