Abstract: By studying the average effect of the electronegativity of alloy and compound superconductors, some empirical laws are found. The average value of the electronegativity of alloy superconductors $\overline{\chi}$ is from 1.3 to 1.9, most of which is concentrated in the region $1.5<\overline{\chi}<1.8$. The $\overline{\chi}$ of many higher T_c superconductors is nearly 1.60. All these characteristics are similar to element superconductors. The average value of the electronegativity $\overline{\eta}$ of positive valence elements in oxide superconductors is from 1.3 to 1.6, and the average effect of an electronegativity of zero on every element $\overline{\zeta}$ is from 1.75 to 2.00. The mean of $\overline{\eta}$ and  $\overline{\zeta}$ is from 1.5 to 1.8. When both $\overline{\eta}$ and $\overline{\zeta}$ are near the limit value (1.3 or 1.6 and 1.75 or 2.00), the material has a very low T_c, even is non-superconductive. The $\overline{\eta}$ of other compound superconductors is either too high or too low, and the $\overline{\zeta}$ is too low so that the T_c of these superconductors is quite low. Studying the average effect of the electronegativity of non-superconducting compounds further confirms the laws. 

Key words: superconductivity, electronegativity, empirical law