After the founding of New China, Wu Nanshan successively served as the captain of the Public Security Corps of Lanzhou Public Security Bureau, the captain of the Public Security Corps of Gansu Provincial Public Security Bureau, the director of materials of Lanzhou City, and the director of materials of Pingliang Special Zone.

Wu Nanshan, 1939, was introduced to join the military Chinese training class. Since the end of 1939, military agents trained by Hanzhong special training class have been sent to Yan' an base area to lurk. South was sent by the military to Longdong base area, and soon made a report to the * * * production party.

The Central Social Affairs Department in charge of security thought that the case was particularly serious and must be seriously detected, so Wu Nanshan was assigned to send special agents to Hanzhong special training class for reconnaissance. Subsequently, Wu Nanshan identified and arrested Qi Sanyi, a latent agent of the military system. After Qi Sanyi was arrested, he gave up 20 dispatched agents. Through the clues of these 20 people, he has been arresting 32 hidden military agents. After the case was detected, it caused great shock in the Shaanxi-Gansu-Ningxia border region.