The Japanese X-ray Astronomy Satellite, Hitomi (ASTRO-H) carries hard X-ray imaging system, covering the energy band from 5 keV to 80 keV. The hard X-ray imaging system consists of two hard X-ray telescopes (HXT) and the focal plane detectors (HXI). The HXT employs tightly-nested, conically-approximated thin foil Wolter-I optics. The mirror surfaces of HXT were coated with Pt/C depth-graded multilayers. We carried out ground calibrations of HXTs at the synchrotron radiation facility SPring-8/BL20B2 Japan, and found that total effective area of two HXTs was about 350 cm2 at 30 keV, and the half power diameter of HXT was about 1.'9. After the launch of Hitomi, Hitomi observed several targets during the initial functional verification of the onboard instruments. The Hitomi software and calibration team (SCT) provided the Hitomi's data of G21.5-0.9, a pulsar wind nebula, to the hardware team for the purpose of the instrument calibration. Through the analysis of the in-flight data, we have confirmed that the X-ray performance of HXTs in orbit was consistent with that obtained by the ground calibrations.