Sensitivity quality of thermocouples is an important parameter in temperature measuring, it affects on the accuracy of measuring results. Metals type which used in thermocouples play a prominent role in determining level and quality of sensitivity. Nine minerals were investigated and compared with each other, as these metals contribute to composition of six thermocouples of types E, J, K, T, R and S. Three factors such as metal type, magnetic field, and chemical composition were studied to find out their effects in determining sensitivity quality of thermocouples due to their effects on the increasing and decreasing of sensitivity and accuracy of thermocouples. Research methodology has used data collection and analyzing on related 6 thermocouples. The results showed that E-type has higher sensitivity, then J, K, and T, but R and S types have lower sensitivity in most temperature measuring ranges, also, copper, nickel, and chromium can give higher quality of sensitivity more than platinum and rhodium. Also, the results of this research can assist manufacturers to further connection between quality of sensitivity, temperature ranges, and accuracy, in addition, for selecting appropriate metal for the medium being measured.