According to the general grading standard, 70 points in the sampling results of doctoral thesis are unqualified. In the evaluation of doctoral dissertations, it is generally considered that more than 90% are excellent, 75% are qualified and less than 70% are unqualified. This is because doctoral thesis is an important achievement of higher academic research, which requires higher academic level and research quality. Therefore, obtaining a sampling result below 70 points means that the paper has obvious defects in academic quality, research methods or argumentation logic.