A Hakka, Wu was born in the village of Ho Hau, Wu-hua (Province of Guangdong, Diocese of Kai-ying).

On 25 March 1985, he led a five-member delegation on a seven-day visit to Beijing and Shanghai, at the invitation of the National Bureau of Religious Affairs under the State Council of China.

After the Tiananmen Square protests of 1989, on 11 July 1989, he wrote a letter to all the bishops in the world, requesting them to appeal for justice, order and democracy in China.

He died of cancer and diabetes on 23 September 2002 at Queen Mary Hospital in Hong Kong, aged 77.

On September 2022, twenty years after his death, Wu's remains were exhumed and re-interred in the Crypt of The Cathedral of the Immaculate Conception.