The invention discloses a dual-polarized built-in slot antenna used for a mobile terminal of a wireless local area network, which belongs to the field of antenna design and is characterized in that: a coplanar waveguide feed structure on the facade of a printed circuit board can simultaneously support an odd symmetric feed mode and an even symmetric feed mode to excite a horizontal polarization mode and a vertical polarization mode of the slot antenna inside the facade metal of the printed circuit board respectively so as to realize two orthogonal polarization modes in the same radiation unit, and meanwhile is excited by two orthogonal transmission modes of the same feed structure. The dual-polarized internal slot antenna has the advantages of miniaturization, broad band, compact structure and high isolation, and is suitable for the antenna of a multi-input multi-output system of a miniaturized mobile terminal on behalf of wireless local area network services.