The temperature dependences of the magnetic susceptibility χ (T) of diluted magnetic semiconductor HgSe:Ni (1·1018 < NNi < 1·1019) cm-3 were investigated. It was found that paramagnetic part of the susceptibility which is wholly due to the effect of the impurities in the range of temperature from 1.8 to 200 K is described by the Curie-Weiss law. The analysis of the concentration dependence of the Curie constant C(NNi) based on the model of the hybridized electronic states was carried out. The application of this model allowed us to determine the microscopic parameters of the electronic structure of these crystals (the effective spin of the hybridized electronic states at the nickel impurity Si and the resonance concentration of donor electrons n0d).