Before moving to New Zealand, he was a member of the Chinese Communist Party and worked for the People's Liberation Army, including training linguists to intercept foreign communications.

[10] While he was initially re-selected as a National Party list candidate in March 2020 for that year's general election,[11] Yang later announced his retirement from politics following renewed pressure from New Zealand First MP Winston Peters over his alleged links to Chinese military intelligence.

[12][13][14] It was later reported that his retirement from Parliament came as the result of a secret deal between Prime Minister Jacinda Ardern and Opposition Leader Todd Muller after intelligence agencies raised concerns about his and Labour MP Raymond Huo's relationships with the Chinese Government.

In response to the accusations, the National Party released a copy of Yang's CV from 2012, which mentioned his time at the Air Force Engineering College and Luoyang People's Liberation Army University of Foreign Languages.

[22][23][24] He then announced his retirement from Parliament, reportedly as a result of a deal between Prime Minister Jacinda Ardern and Opposition Leader Todd Muller after intelligence agencies raised concerns about his and Labour MP Raymond Huo's relationships with the Chinese Government.

[3][4][5] First-term National Party list MP Nancy Lu was sitting in an interview with Chinese-language media outlet Panda TV37 next to Dr Jian Yang in 2020 when the outgoing MP and alleged Chinese spy admitted he handpicked Lu to be his successor, saying he had “trained” her to stand for the party “for a long time” and kept it secret from his colleagues: as reported by J. Wong, Stuff, 20 June 2024.