Xi urged to establish mechanisms to restrain and supervise power, and ensure that "power be made responsible and be supervised, and violations of law be investigated."
He also urged to "ensure that the power bestowed by the people is constantly used for the interest of the people."
The National People's Congress, China's top legislature, and its standing committee as well as other supervisory organs should take the responsibility to strengthen reviews and inspections on the enforcement of the Constitution and the laws, Xi said.
Supervision mechanism and procedure of the law enforcement should be improved to firmly correct behaviors violating the Constitution and laws, he said.
"We should endeavor to let the people experience fairness and justice in every judicial case, and should never allow unjust judgement infringing people's rights and interests," Xi said.
China's top legislature adopted the Constitution on Dec. 4, 1982, based on a pervious version enacted in 1954.
Prof. Wang Zhenmin with Tsinghua University, who attended Tuesday's meeting, said Xi's pledge to respect the Constitution will be supported by the academic circle.
Teng Yongshuang, vice president of the People's Court of Pingdu City in east China's Shandong Province, said the move will promote judicial justice at grassroots.
Top legislator Wu Bangguo presided over Tuesday's commemoration congress. Li Keqiang, Zhang Dejiang, Yu Zhengsheng and Liu Yunshan, all members of the Standing Committee of the Political Bureau of the CPC Central Committee, attended the congress.