The once-in-a-five-year Congress, which will conclude on October 24, will see Ji Xinping establishing a firm grip over the country's all powerful Communist party.
Much of it is expected to focus on the party's achievements during Xi's first term.
The congress also decided the roadmap for China for the next five years, and was expected to finish next week.
Chinese President and Communist Party chief Xi Jinping kicked off his party's once every five-year national congress on Wednesday, a rare rainy day for the autumn season, delivering a keynote speech outlining his vision for a second term as party head.
The Chinese authorities have raised security measures in Beijing ahead of the party congress, including stricter luggage scans at transportation hubs and deployment of paramilitary units at subway stations.
Currently, the seven-member Standing Committee of the Politburo, which literally governs the country, is headed by Mr Xi, 64, who besides being the general secretary of the party is also China's President and head of the military.
However, there is a high security alert.
An austerity drive instituted by Mr Xi has meant a more pared down congress, with Chinese reports this week of delegates' hotels cutting back on frills such as decorations, free fruit in rooms and lavish meals.
State media have said the Party was expected to rewrite its constitution to include Mr Xi's "work report" or political thoughts, which would elevate him to the status of previous Party giants Mao Zedong and Deng Xiaoping.
China, which Xi said is the world's "largest developing country", is now the world's second largest economy and has the second largest stock market.