The invention discloses a transformer structure with enhanced coupling degree. The transformer structure comprises bottom layer metal used as reference ground of a transmission line structure, an input structure and an output structure, and a primary coil and a secondary coil, wherein the input structure and the output structure are used for conversion of a quasi-TEM transmission mode and a surface wave propagation mode on the transmission line to enable electric field energy to be distributed on one side of a periodical stub to lower signal crosstalk, wherein the input structure and the output structure both adopt a back-to-back structure; and the primary coil and the secondary coil both adopt a periodical stub structure to enable the electric field energy to be distributed in the periodical stub structures of the primary coil and the secondary coil to reinforce magnetic field strength between the coils so as to improve the coupling degree of the transformer. By adoption of the periodical stub structures, the transformer coupling degree, particularly in the millimeter-wave frequency band can be reinforced, thereby reducing a crosstalk phenomenon between adjacent lines, and reinforcing magnetic induction strength in the coils.