Cumulative class hours and teaching class hours in teachers' professional titles are two important indexes to evaluate teachers' professional titles. The difference between them lies in the following points:

Cumulative class hours refer to the total length of teaching courses accumulated in a teacher's career. Including teachers' teaching time in schools, training institutions and other teaching places at all levels.

Teaching hours refer to the number of hours a teacher serves as a student guide or teaching work in his career. Including providing students with academic guidance, scientific research guidance or participating in other activities related to student guidance.

To sum up, the cumulative class hours mainly calculate the total time for teachers to engage in teaching activities, while the teaching hours emphasize the time for teachers to guide students. These two indicators will be considered when evaluating teachers' professional titles, but the specific evaluation criteria and weights may be different. The specific evaluation criteria and requirements can be different according to different regions, different schools or different professional titles.