To forecast the properties of the HfC1-xNx solid solutions, their valence electron structures were analyzed and compared with those of the HfC and HfN matrix on the base of the empirical electron theory (EET) of solids and molecules. The results showed that, when the HfC and HfN dissolved each other, the step numbers of two nonmetallic atoms (C and N) were invariable, and the step number of Hf element increased form B11 to B16. With the x value increasing, the covalent electron amount and the bond energy on the strongest bond and the melting point, all dropped gradually, while the percentage of total covalent bond number increased, indicating that the hardness, bond energy, melting point and toughness decreased, and the strength increased.