Export special characters to excel came to mass

I am a beginner of using Laravel-4.2.

I try to extract data from database (mySQL) which contains Chinese characters and export to excel file. It came out mass. Tables collation are defined utf8-utf8_unicode_ci.

I have been searching since now and then, it seems no solution.... i found a suggestion to concate "\xEF\xBB\xBF" in front of the data, but it doesn't work....

Please Help