The terahertz polarization manipulation technology based on electromagnetic metasurface is studied. Specifically, a reflective-type terahertz 90o linear polarization converter is designed by using the metal-dielectric-metal sandwiched structure, and the polarization conversion characteristics are investigated both numerically and experimentally. It is shown that the reflective-type metasurface designed in this work achieves a high polarization conversion efficiency(above 75%) at the operating frequency of 0.5 THz as well as a broad working band(the polarization conversion efficiency is more than 50% over the frequency range of 0.35-0.65 THz). In addition, the ultrathin glass substrate produces the excellent overall performances of the metasurface linear polarization converter, including small thickness, light weight, and good heat resistance.