Abstract: Baroclinic instability theory reveals a fundamental instability mechanism for large scale atmospheric perturbations, especially over the middle and high latitudes. It is also an important progress in the dynamic meteorology after the establishment of long wave theory, and still important for modern weather forecast. This paper focuses on the evolution of baroclinic instability theory and reviews the contributions by Charney, Eady and Jaw. Jaw's research is one of the earliest studies in view of baroclinic instability. A critical wavelength of the instability was proposed, and the energy conversion and its possible influence on atmospheric circulation were also analyzed. His research was undisputably progressive at that time. In 1947, by the wave filtering and scale analysis, Charney simplified the equation of atmospheric disturbance to make it able to be solved. He deduced the criterion for the stability, and established the baroclinic instability theory. As its by-product, the quasi-geostrophic theory made the numerical weather forecast to be successful for the first time. In 1949, based on the work of Charney, Eady obtained a more simplified model. By comparing their research ideas, this paper summarizes the reasons why Jaw could not build the theory one year ahead:the vertical movement and the essence of the genesis and development of weather system were not considered in his study, which led to the final failure. And because of this reason, some of the highlights in his paper were neglected.