The congress will hear and review a report by the 17th CYL Central Committee, amend the CYL constitution and elect the 18th Central Committee, the Xinhua News Agency reported.
The CYL's national congress gathers 1,500 representatives from across the country and has been convened every five years since the 1990s.
How to carry out the CYL's reform plan, which was put forward by the Communist Party of China (CPC) Central Committee, is expected to be a key issue at the congress, Zhuang Deshui, a professor from Peking University, told the Global Time.
The CYL reforms require it to better perform its duty of serving the youth and become a link between the Party and youth, said Zhuang, adding that the league had previously been criticized as overly bureaucratic and inefficient.
The general office of the CPC Central Committee published a plan for reform of the CYL Central Committee in August 2016, noting that the staff structure, organization and operation of the leading organ of the CYL Central Committee will be improved, said Xinhua.
Another highlight of the congress will be to set Xi Jinping Thought on Socialism with Chinese Characteristics for a New Era as the guiding principle of the CYL, which was written into the Party Constitution during the 19th National Congress of the CPC, Su Wei, a professor at the Party School of the CPC Chongqing Committee, told the Global Times.
With over 81 million members, the CYL is tasked with organizing activities and bringing forward progressive ideas under the leadership of the CPC. It acts as the assistant and a recruiting source for the CPC. Young people between the ages of 14 and 28 can join the CYL.
Efforts to improve
Both Zhuang and Su said the CYL has made great efforts to improve its images and work style over the past several years, and has become a real "friend" of the Chinese youth.
"The CYL is active online, and its social media accounts frequently comment on hot topics and raise sharp opinions which are close to younger people," Su said.
The CYL gained popularity among young people after it became active on popular social media channels. The CYL's Weibo account, which was opened in December 2013, had more than 6 million followers as of Tuesday.
In early 2017, CYL joined Bilibili, a video-sharing website specializing in anime, comics and games. It also invited members of the popular boy band TFboys to be its ambassadors.
Su said the key next step for the CYL is to deepen reform, especially in the reform of its leadership.
According to the CYL's reform plan, it will encourage more of its leaders to work only part-time, and include more input from grass-roots CYL organizations and members.
"But how to ensure that those part-time leaders could balance their duties with their full-time job is a challenge of the current reform," Su said.
"The leaders of CYL should focus on serving, educating and unifying the youth, rather than using their positions to seek personal gain," Zhuang said.
Historically, the CYL provides one of the main paths to political development in China.
Newspaper headline: Communist Youth League convenes its 18th congress