Solution : https://service.sap.com/sap/support/notes/1670378 (SAP Service marketplace login required)
Key words : 
control panel -> sap gui configuration ->sap gui options dialog, uniformly calculated line spacing/font size, goto visual design -> font setting, sap gui textedit, 'fixed width font settings', symptom chinese characters displayed, font settings reason, change font settings, unicode backend system, chinese characters
Related Notes : 
       
| 1053737 | Expected release dates for SAP GUI for Windows & ITS Patches | 
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| 535308 | How to apply a SAP Front End patch? | 
| 330793 | Downloading patches |