The cross is an important symbol in Christianity and a mark of belief. Originally, the cross was a cruel instrument of torture in the ancient time, but it gained the favor of Christianity and became an object of worship in the end. The reason lies in that it embodies the cultural spirit of Christianity, symbolizes the reciprocal philosophical concepts of "restriction and liberation", "death and revival", and represents the basic organic structure of "vertical composition and horizontal gathering". On the one hand, the cross symbolizes death-the crucifixion of Jesus Christ; on the other hand, it also symbolizes "resurrection", because Jesus came to life three days later after he was crucified. That is to say, in the process of the death of his body, his spirit revived. So, we can say the cross is the symbol of "Phoenix nirvana".