Yes. It is against the law to be a Chrisitan in China. It is also important to understand that Christians are persecuted in every country, even when it's not illegal. Insulting a Christian because of their religon is also classed as persecution. However, Christians also know that God is always with them and shares their pain when they are persecuted. Matthew 28 v 20 Teach them to obey everything that I have taught you, and I will be with you always, even until the end of this age.