I'm a christian guy wants to marry a hindu girl,can we marry in the church without converting her religion?

You are best to check with the minister of the church you both wish to be married in.

She may not have to convert, but she may be required to take a pre marriage course, and other meet other requirements.

It depends on your local church , in America there are 100's of different Christian churches even independent ones. So in America, yes it is allowed in many. ( but not in others)
Here in China, there is only one official "Christian" church, but marriage is done by the governmetn only, with just a blessing in the Church