To build camaraderie or strengthen cooperation within a group; abbreviation for 团队建设 tuán​duì​jiàn​shè

Refers to organizational activities and development within the Chinese Communist Youth League; short for 中国共产主义青年团建设 zhōng​guó​gòng​chǎn​zhǔ​yì​qīng​nián​tuán​jiàn​shè