Can I attend Mass and receive Communion in a Chinese church that is not recognized Holy See?
I assume that you are referring to a Chinese Patriotic church in China, where the Catholic churches recognized by the Holy See have been driven underground.
Canon law provides:
Whenever necessity requires or a genuine spiritual advantage commends it, and provided the danger of error or indifferentism is avoided, Christ’s faithful for whom it is physically or morally impossible to approach a Catholic minister, may lawfully receive the sacraments of penance, the Eucharist, and anointing of the sick from non-Catholic ministers in whose hurches these sacraments are valid (canon 844 §2).
Since you are presumably traveling in an area where you cannot reasonably attend a recognized Catholic church, and presuming that the Chinese Patriotic church in question maintains valid sacraments, generally speaking it is possible to receive the sacraments at such a church, especially if one is in danger of death.
However, unless there are grave mitigating circumstances such as the danger of death, I cannot recommend attending Mass at or receiving the sacraments from priests of this schismatic church. Given the situation in Communist China – where faithful Catholic priests, bishops, and laypeople have been horribly treated and even martyred for the faith – I cannot recommend giving the appearance of support to the nationalist church that has accommodated to the Communist Chinese government. Besides, when Catholics travel in an area where there are no recognized Catholic churches, they are not bound by the Sunday and holy day obligations.