The study of analytical mechanics mainly includes two aspects: the exploration of physical significance and the application of mathematical methods, which should be developed in coordination. Based on dimensional analysis, the inverse problem of Lagrangian mechanics was taken as an example to reveal that the physical significance of the study on analytical mechanics should be emphasized. Specifically, two questions should be answered: (1) whether new results affect the original physical conclusion, and (2) whether new results and methods are inconsistent with the laws of physics. Two examples were given to support this point.