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 x is from 1.3 to 1.9, most of which is concentrated in the region 1.5 < x < 1.8. The x of many higher Tc superconductors is nearly 1.60. All these characteristics are similar to element superconductors. The average value of the electronegativity η 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 is from 1.75 to 2.00. The mean of η and is from 1.5 to 1.8. When both η and are near the limit value (1.3 or 1.6 and 1.75 or 2.00), the material has a very low Tc, even is non-superconductive. The η of other compound superconductors is either too high or too low, and the is too low so that the Tc of these superconductors is quite low.Studying the average effect of the electronegativity of non-superconducting compounds further confirms the laws.