High output power terahertz(THz) quantum cascade laser based on tapered waveguide profile is fabricated. Semi-insulating surface-plasma waveguide structure and tapered profile are adopted to enable high output power and excellent far-field lobe profile. The Full Width at Half Maximum(FWHM) of the laser beam in the horizontal direction is 18.4?. The emission wavelength is centered at 93 μm(3.23 THz), the highest output power is 185 mW and the highest operation temperature is 95 K. The output power at 80 K is 65 mW. Based on the high output property, portable terahertz laser source is packaged by liquid nitrogen dewar.