Could you please specify what do you mean by writing Chinese text from TestComplete into an html page?
Are you trying to write Chinese text to an html file stored on your computer, or are you trying to insert Chinese text into some edit box of a web site?
If you are trying to write Chinese text to a file, could you please specify what methods are you using? Are you using the aqFile.WriteToTextFile method?
If you are trying to insert Chinese text into some edit box on a web page, please check whether your web browser uses the encoding that supports Chinese characters.