According to "Letter of the Holy Father, Pope Benedict XVI, To the Bishops, Priests, Consecrated Persons, and Lay Faithful of the Catholic Church, in the People's Republic of China:"
... sacraments administered by such Bishops and priests are likewise valid.
More details if you don't want to read the whole letter yourself:
In Section 8 of the letter, he talks about the Chinese Episcopate and mentions a few different groups of Bishops:
There are some:
...Bishops who have received episcopal ordination in conformity with Catholic tradition, that is to say, in communion with the Bishop of Rome, Successor of Peter, and at the hands of validly and legitimately ordained Bishops in observance of the rite of the Catholic Church.
There are also:
Other Pastors, however, under the pressure of particular circumstances, have consented to receive episcopal ordination without the pontifical mandate, but have subsequently asked to be received into communion with the Successor of Peter and with their other brothers in the episcopate. The Pope, considering the sincerity of their sentiments and the complexity of the situation, and taking into account the opinion of neighbouring Bishops, by virtue of his proper responsibility as universal Pastor of the Church, has granted them the full and legitimate exercise of episcopal jurisdiction.
These two groups are validly and legitimately ordained Bishops, so of course their administration of sacraments would be considered valid.
Then he talks about another group:
Finally, there are certain Bishops – a very small number of them – who have been ordained without the Pontifical mandate and who have not asked for or have not yet obtained, the necessary legitimation. According to the doctrine of the Catholic Church, they are to be considered illegitimate, but validly ordained, as long as it is certain that they have received ordination from validly ordained Bishops and that the Catholic rite of episcopal ordination has been respected.
Of this last group, he says:
Therefore, although not in communion with the Pope, they exercise their ministry validly in the administration of the sacraments, even if they do so illegitimately.
The full sentence that I excerpted above is:
Concerning Bishops whose consecrations took place without the pontifical mandate yet respecting the Catholic rite of episcopal ordination, the resulting problems must always be resolved in the light of the principles of Catholic doctrine. Their ordination – as I have already said (cf. section 8 above, paragraph 12) – is illegitimate but valid, just as priestly ordinations conferred by them are valid, and sacraments administered by such Bishops and priests are likewise valid.
In the very next sentence, he says that the faithful should seek Bishops and Priests who are in communion with the Pope, but:
... where this cannot be achieved without grave inconvenience, they may, for the sake of their spiritual good, turn also to those who are not in communion with the Pope.