That values the four-year old firm at nearly $15bn (?10bn) makes it one of the world?s most valuable start-ups.
Snapchat allows users to send text and picture messages which disappear in 10 seconds.
Snapchat says its users send 700 million snaps daily, recently started generating revenue from advertising.
The $15bn valuation puts the business in a league with taxi service Uber and Xiaomi, the Chinese smartphone maker.
Alibaba has invested in a range of start-ups in China, but its portfolio in the US is relatively small.
The company has stakes in video call app TangoMe and Lyft, a competitor to Uber.
BBC
