Ph.D. in Hong Kong Polytechnic University lasts for 4 years. In general, the length of doctoral studies in schools is 3 years, and doctoral thesis is written 1 year. The doctoral degree in the school is a tutorial system, and the tutor decides whether the doctoral thesis is passed or not. Once the tutor thinks that the thesis has reached the graduation level, it will be sent to the peer review nominated by the tutor, and the subsequent defense will also be conducted by the tutor and the review professor.