A mathematical model and a program are developed to calculate neutron yields,energy spectrum and angular distribution of D(d,n)~3He reaction in a thick deuterium-titanium(TiD_x) target as incident deuteron energy lower than 1.0 MeV.D(d,n)~3He reaction cross section from nuclear data tables and stopping power derived with SRIM-2003 code are adopted in the calculatoin of neutron production of an acceleratorbased D(d,n)~3He reaction neutron source.Integrated neutron yields,neutron energy spectrums and angular distribution are obtained.