Described are a method and a device for posting a microblog message. The method includes: acquiring text content input by a user in a microblog text box; monitoring a posting operating instruction for the text content; calculating the number of the characters of the text content; determining whether the number of the characters of the text contents exceeds a preset-threshold; if the number of the characters of the text content exceeds the preset threshold, converting the text content into a format of messages according to a user selection from a plurality of format settings, and posting the format of the messages as a microblog message, or splitting the text content into multiple microblog message being less than the preset threshold; and if the number of the characters of the text content does not exceed the preset threshold, directly posting the text content as the microblog message.