Teaching assistants are the primary level of professional and technical qualifications (titles) of university teachers, followed by lecturers, associate professors and professors (some universities have different treatment levels for professors). Need to pass the evaluation of teacher qualifications, scientific research achievements and other conditions;
Tutor is a special post in colleges and universities, which generally refers to the training qualification for graduate students. Usually only teachers with the title of associate professor or above can get it.
There is no direct promoting relationship among them.