Xi, general secretary of the CPC Central Committee, made the comments at the opening ceremony of a high-profile workshop attended by new CPC Central Committee members and alternate members elected at the 18th CPC National Congress in November last year.
Xi called for efforts to unswervingly uphold and develop socialism with Chinese characteristics, saying "which path to take decides the life of the Party" and it is the most important question that is related to the success or failure of the Party.
CPC members should always harbor the spirit of "cutting a road when (they) come to the hill, and building a bridge when (they) come across a river," Xi said, urging them to "forge ahead and explore boldly" along the path.
CPC members should deepen reform and opening up, make discoveries, innovations and progresses, he said.
He urged Party members to be brave in analyzing and responding to pressing problems that the public want solving and to promote innovation in practice, theory and institutional building.
Late Chinese leader Deng Xiaoping put forward the concept of building socialism with Chinese characteristics 31 years ago.
Xi said China's cause to develop socialism can be divided into two stages by the watershed decision of starting the reform and opening-up in the late 1970s.
Although principles and policies as well as practice in the two stages were very different, they were not irrelevant nor contradicted with each other, he said.
Socialism with Chinese characteristics took shape after the country adopted reform and opening-up. However, it was also based on the socialist system established since 1949 and the following 20-plus years of socialist construction, he said.
People can not deny what was done before the reform and opening-up based on what happened after it and vice versa, he said.
"We should seek the truth from the facts and tell apart what is important and what is not," he said.
After China's late leader Deng Xiaoping set the basic principles for socialism with Chinese characteristics, the third generation of central collective leadership with Jiang Zemin at the core and the leadership with Hu Jintao as the general secretary left remarkable marks on the cause of socialism with Chinese characteristics, Xi said.
"Our generation's mission is to carry on this great work," he said. "As our cause moves forwards, new problems will emerge as well as risks and challenges. We will have to handle more unpredictable situations."
The CPC should be prepared for potential dangers and risks in times of peace, he said.
He also urged all CPC members to embrace the ideal of communism, believe in and practice socialism with Chinese characteristics.
A CPC member, especially a leading official, should serve the people with heart and soul, devote himself to hard work and perform his duties honestly, he said.
Xi also warned those who confuse, hesitate, indulge in luxuries, seek profits for themselves and shrink away from actions.
He said upholding and developing socialism with Chinese characteristics was the theme of the report to the 18th CPC National Congress, which was delivered by Hu Jintao on Nov. 8.
"Socialism with Chinese characteristics is the only route that must be taken to complete the building of a moderately prosperous society in all respects, advance the socialist modernization and realize the great rejuvenation of the Chinese nation," he said.
Li Keqiang, a member of the Standing Committee of the Political Bureau of the CPC Central Committee, presided over the workshop's opening ceremony. Li said Xi made a profound elaboration on major theoretical problems in today's China and urged all participants to study his speech and implement it.
Also present at the opening ceremony were other members of the Standing Committee of the Political Bureau of the CPC Central Committee, including Zhang Dejiang, Yu Zhengsheng, Liu Yunshan, Wang Qishan and Zhang Gaoli.