In the late 1920s, Cai Zejuan, who was born in Wangmen, Ningde, went to Shanghai to study at Tongji University. He secretly searched for party organizations in Shanghai, which attracted the attention of the Central Military Commission's Special Branch Mingsong.After several trials, Cai Zejun's identity as a Communist Party member was finally confirmed, and he accepted the organization's arrangements. Under the pseudonym Cai Wei, he went to the Soviet areas of Hubei, Henan, and Anhui to prepare for the establishment of a radio station.After arriving in the Hubei-Henan-Anhui Soviet Area, Cai Wei used his radio expertise to establish the first radio station for the Fourth Red Army with Xu Zhengye and Qu Xiangdong, and also trained a group of radio talents.

Cai Wei was unwilling to accept that the radio station could only be used for sending and receiving messages. He began to study the deciphering technology to intercept the enemy's military information. He used his mathematical talents to decipher enemy codes again and again, gain insight into the troop mobilization of the Kuomintang army, and provide information for the Red Army in the Soviet area to break the enemy's encirclement and suppression plan.provided strong intelligence support.In the two major battles against the three-pronged siege and the six-pronged siege, the intelligence provided by Cai Wei and his comrades helped the Red Army troops avoid danger time and time again. However, Cai Wei fell ill due to overwork in Zhuoping Village, Min County, Gansu Province and died.young life.