Ni was born in Ningbo, Zhejiang, but grew up in Shanghai. He worked as a public security official under the Chinese Communist Party (CCP) government in the 1950s in Inner Mongolia and was tasked with writing death sentences. He once questioned the local party chief about why a particular man was sentenced to death, when the offence he committed (as stated on paper) was for being a landlord. The chief threatened to execute him if he continued to ask questions. According to Ni, he complied with the order because he feared for his own life. This was not the only instance in which Ni wrote a questionable death sentence which was categorised under "others" by the CCP government. These experiences made Ni decide to escape from China to Hong Kong in 1957.