Five years. Dr. Tsinghua University is divided into three types, namely, direct PhD, general PhD and in-service PhD. The direct doctoral program lasts for 5 years; Pubo is 3 to 4 years; On-the-job blogging is three to four years, just like Pubo. Direct doctoral students are all called undergraduate direct doctoral students, which means that after graduating from undergraduate this year, they skip the postgraduate stage and study for doctoral degrees directly as doctoral students.