Abstract: Thermal desorption spectroscopy (TDS) is one of the most popular methods to investigate hydrogen isotopes diffusion, trapping and retention in materials. For accurately measuring the desorption and retention behavior of deuterium and helium in a single specimen, a high resolution thermal desorption spectroscopy experiment system called HiTDS was introduced in this paper. HiTDS realizes ultrahigh background vacuum of 1.2×10^-6 Pa, a constant rate of 1 K/s and the maximum temperature of 1423 K. HiTDS also achieves rapid separation of helium and deuterium molecule mixed signals efficiently via a high resolution quadruple mass spectrometer. After tuning operation and sensitivity calibration, measurements of pure deuterium and deuterium/helium synergistical desorption from plasma irradiated tungsten were accomplished via HiTDS. TDS results reveal that deuterium/helium plasma induced damage becomes severe with the increase of fluence while deuterium retention reaches saturation because of helium inhibiting effect on deuterium diffusion and reservation, and the validity of the experiment turns out to be favorable.