In March 1939, with the approval of the Yunnan Provincial Working Committee of the Communist Party of China, the Luoping County Committee of the Communist Party of China was established, with Wu Shilin as a member of the county committee. At this time, the focus of the party's work has shifted from cities to rural areas. The party organization requires every party member to completely change their style of work and go to the countryside to do the party's work in a down-to-earth manner. Wu Shilin set an example by moving his family members from Banqiao Town to Xujia Garden on the outskirts of the city. Using this as a center of activity, he went deep into nearby villages such as Xincun, Songmaoshan, Chelu, Dashuijie, and Bailongtan to secretly mobilize and organize " "Peasant Group" and "Brotherhood", opened "Peasant Night School" and "Farmer Literacy Class", and successively developed more than 100 members of "Peasant Group" and "Brotherhood", cultivated the backbone of farmers and strengthened the revolutionary force. At the end of the year, Luoping launched a cultural movement. Wu Shilin and progressive teacher Yin Lanbing led school teachers, students and some social youths to join the "Puppet Pulling Movement", and the clay Bodhisattvas from the Chenghuang Temple, Wanghuang Pavilion, Xiangshan Temple, Baiyi Temple, Qinglin Temple and other temples were gathered together. Pull down. This move was so powerful that it shocked the urban and rural areas of Luoping and affected Shizong, Luliang, Pingyi and other counties.

On June 20, 1940, Wu Shilin learned from the Kuomintang Luoping County Party Headquarters: Yan Xu, the enemy brigade commander stationed in Luo, conspired with the county magistrate Liao Wenwei and the county party secretary Li Zesheng in an attempt to track down "suspects of alien parties" ". Kill the Luoping underground party. He immediately avoided enemy surveillance and cleverly sent the information to Luoping Middle School and handed it over to the underground party organization, allowing the underground party to gain time and quickly transfer or destroy important party documents and books in advance. When the enemy sent troops to search the middle school, nothing was found. Wu Shilin made important contributions to protecting the party's security.

In 1941, the Kuomintang reactionaries launched the second anti-Japanese upsurge and created the "Southern Anhui Incident" that shocked China and foreign countries. In response to this situation, the party further implemented the 16-character policy of "securing capable personnel, lurking in ambush for a long time, accumulating strength, and waiting for the opportunity" and the instructions of "three diligences" and "three modernizations". During this period, Wu Shilin founded Xingsheng Charcoal Society in Longjing Street, Kunming, based on his work needs and through private fundraising. On the surface, he sold charcoal, salt, rice and other miscellaneous commodities, but secretly used it as a contact point to arrange evacuation and transfer. Kunming - The work, food and accommodation of underground party members and progressive young people who could not find jobs at that time played a good role in sheltering capable people and accumulating strength. During this period, Wu Shilin was appointed as an organizational member of the Workers' Movement Committee of the Yunnan Provincial Working Committee of the Communist Party of China. He often went deep into factories and mines, talked with workers, made friends, organized trade unions, launched and led workers in Kunming Power Plant, Dazhong Printing Factory and other strikes to demand the implementation of an eight-hour work system, improve working conditions, and increase wages, forcing the authorities to make certain measures. The concessions also exercised the workers in the movement.