Answer: You should apply for renewal of your motor vehicle driving license within 90 days before the expiration of its validity.

According to the relevant provisions of Article 63 of the Regulations on the Application and Use of Motor Vehicle Driving Licenses (Order No. 162 of the Ministry of Public Security):

The driver of a motor vehicle shall, within 90 days before the expiry of the valid period of the motor vehicle driving license, apply to the vehicle management office at the place where the motor vehicle driving license is issued or outside the place where the license is issued.