The rates of 14N/12/C in wheat seeds wene measured by using 14N(d, p)15N and 12C(d,p) 13C reactions induced by 13.4MeV deuterons which wene produced by a cylotron. According to the measured 14N/12C rates, the relative protein contents in different wheat sorts were defermined and compared with the results obtained by the Kjeldahl method.