"天坛大佛" can be translated into English as "Tian Tan Big Buddha" or more commonly and formally as "The Big Buddha at Tian Tan Temple" (though "Tian Tan" is often directly referred to as "Tian Tan" in English contexts related to this landmark, and the full translation may vary slightly based on context and preference).
In most international contexts, especially when referring to the specific statue in Hong Kong, it is simply known as "Tian Tan Buddha" or more formally and recognizably as "The Tian Tan Buddha" or "The Big Buddha of Tian Tan". The most widely recognized and concise translation, however, is "Tian Tan Buddha".