this kind of tracking number starting with U is china post ordinary parcel. you can track its shipment effect date and original post office in http://track-chinapost.com/startairmail.php .

This is a slow and cheap service for low value item. China Post will not scan and update its status after it left first post office. so you can not see new status and know where it is now. china post ordinary parcel might take 4 to 12 weeks to reach your country.