Priceline Group Inc. plans to invest $500 million investment in Chinese online travel company Ctrip.com International Ltd., as the online reservation company seeks a larger footprint in the world's biggest outbound-travel market.

Under the deal, Priceline's Booking.com hotel-booking site will advertise Ctrip's inventory of hotels in China. Ctrip, meanwhile, will be able to offer its users a wider array of deals from Priceline's platforms, including Booking.com, Agoda.com for smaller hotels, OpenTable for restaurants and rentalcars.com....