The present teaching relates to automatic formality classification and transformation of online text items. In one example, a request is received for transforming a formality level of a text item in an online communication. A current formality level of the text item is obtained. The current formality level represents a current degree of formality of the text item. A target formality level is determined for the text item based on the request. The target formality level represents a targeted degree of formality for the text item. The text item having the current formality level is transformed to a transformed text item having the target formality level. The transformed text item has a same literal meaning as the text item. The transformed text item is provided as a response to the request.