We report the design, fabrication, and measurement of an ultra-broadband wide-angle reflective cross-polarization convertor using the compact H-shaped metasurface. The significant bandwidth expansion is attributed to the four electromagnetic resonances generated in an H-shaped unit. The simulation results show that the polarization conversion ratio (PCR) of the proposed metasurface is above 90% in the frequency range from 7 to 19.5 GHz and the relative bandwidth reaches 94%. The proposed metasurface is valid for a wide range of incident angles, and the mean polarization conversion ratio remains 80% even though the incident angle reaches 41.5°. The experimental results are in good agreement with the simulation results. Compared with the previous designs, the proposed linear polarization converter has a simple geometry but an excellent performance and hence has potential applications in microwave communications, remote sensors, and imaging systems.