Mountain Lion will include over 100 new features, including Messages, Notes, Reminders and Game Center which are familiar to users of Apple's mobile devices powered by the iOS operating system.
The software, Apple's first OS X after the company launched its iCloud cloud-computing service, will enable users easily set up the service and access documents across their devices.
The developer preview of Mountain Lion also introduces Gatekeeper, a security feature that gives users control over which applications can be downloaded and installed on their Macs.
With an eye on the fast growing Chinese market, Mountain Lion also has a number of features specifically designed to support Chinese users, including significant enhancements to the Chinese input method and making Chinese search engine Baidu an option in the Safari web browser, as well as system-wide support for the Chinese micro-blogging service Sina weibo.
"The Mac is on a roll, growing faster than the PC for 23 straight quarters, and with Mountain Lion things get even better," Philip Schiller, Apple's senior vice president of worldwide marketing, said in a statement.
Latest numbers from Apple showed that the company sold a record 5.2 million Macs during the fourth quarter of 2011, representing a 26-percent unit increase over the year-ago period.