Charles is a distinguished French inventor, scientist and balloon pilot, a legend in the history of balloon development. The famous French chemist and physicist Gay-Lussac, similarly as Charles, is a pioneer in the development of hot air balloons and gas laws. Both of them contributed significantly to the creation and development of gas laws. However, the Charles's law and Gay-Lussac's law are always confused in the elementary education stage. This article mainly introduces the origin, development and naming of Charles's law and Gay-Lussac's law, and explains why they are confused.