Why does Dalian Naval Academy have a marine police major?

There is no marine police major. Official website of Dalian Naval Academy shows that there are seven undergraduate majors: navigation technology, communication engineering, electronic information engineering, weapon system and engineering, detection guidance and control technology, surveying and mapping engineering and military oceanography. And a group of on-the-job officer training (rotation training) majors, including China Academy of Engineering 1 person, 5 distinguished academicians, more than 200 professors and associate professors, excellent teachers of the whole army 15 people, and experts enjoying special government allowance from the State Council 13 people.