"Let them live daily lives practising their faith... without being afraid to speak of Jesus," the pontiff said.
Pope Francis said he prayed that China's Catholics would receive "the grace to announce Christ with humility and joy and to be faithful to the Church and to Peter's successor (the pope)".
China and the Vatican broke off formal diplomatic relations shortly after the Communists took power in Beijing in 1949 and the state-sanctioned Catholic Church (the Catholic Patriotic Association) has installed bishops without Vatican approval.
Pope Francis's predecessor Benedict XVI urged reconciliation between China's 8 to 12 million Catholics, who are divided between the CPA and an "underground" wing loyal to the Vatican, which rejects state control.
Benedict also engaged in a low-key dialogue with Beijing on political ties between the Chinese government and the Vatican, which refuses to recognise the CPA.
But long-running tensions flared up again in July 2012, when the appointment of a Chinese Catholic bishop without the Vatican's approval angered the Holy See, as did the detention under house arrest of the newly ordained bishop of Shanghai, Thaddeus Ma Daqin, who announced he was leaving the CPA.
Observers said Ma's departure from the CPA was seen as a challenge to Chinese state control over Catholic churches and clergy.
In March, China congratulated Francis on his election as pope and called for a "flexible and pragmatic" approach in his relations with Beijing.