Tungsten (W) is one of the primary plasma-facing materials candidate for fusion reactor in the future. It is very significant to carry out a quantitative study on the movement and retention behavior of hydrogen isotopes in W, since it can be used to evaluate the service performance of tungsten and the material balance of fusion reactor fuel. In this work, polycrystalline W was irradiated with 100 eV D⁺ ions to the fluence of 3.8 × 10²⁴ D/m². And the subsequent thermal desorption characteristics of polycrystalline W at different heating rates were investigated by thermal desorption spectroscopy. The tota amount of deuterium desorption is about 10²² D₂/m² orders of magnitude. In particular, the thermal desorption peaks can shift to higher temperature side as the increase of heating rate. The thermal desorption behavior of deuterium in polycrystalline W is in accord with the first order reaction. The vacancies formation is the main trapping state of deuterium, and the thermal desorption energy of D atom is 1.04 eV.