Online travel company Ctrip.com International Ltd and its rival Qunar Cayman Islands Ltd have agreed to a share swap and partnership that will create China's biggest online travel service.

Under the deal, Ctrip will own roughly 45 percent of Qunar, the company said in a statement on Monday.

Baidu, which owns 20 percent of Qunar, will take a 25 percent stake in Ctrip. The two companies will also combine products and services.