In this paper we studied the electron spin resonance in phosphorus-doped silicon, at room temperature and liquid nitrogen, liquid hydrogen temperatures as well as at their temperatures of lower vapour pressure. The concentration for phosphorus impurity is of ～1015—～1018 atom/cm3. A double modulating spectrometer of 3cm band was used.In the experiments, spectral lines for conducting electrons, for surface imperfection centers and for hyperfine structure were observed. The results of experiments also showed the spectral line of interaction between effective electrons and donor nucleus pairs. The g-tactor, the square of the electronic wave function at the donor nucleus,|Ψ(0)|2 , and the electron-nuclear hyperfine interaction constant aD etc., were obtained at 14°K. Our results were approximately in agreement with those obtained by G. Feher at 1.25°K, using electron-nuclear double resonance method.