An identification (ID) code printing method for a glass substrate is disclosed, which comprises the following steps: loading a glass substrate onto a front end of a platform; aligning the glass substrate at the front end of the platform; printing an ID code on the glass substrate for three times in a process of moving the glass substrate from the front end of the platform to a back end of the platform, then from the back end of the platform to the front end of the platform and finally again from the front end of the platform to the back end of the platform. An ID code printing apparatus for a glass substrate is further disclosed. Thereby, an additional cycle of ID code printing operations can be carried out in the present disclosure as compared to the prior art, which can increase the number of times of ID code printing under the conventional tact time conditions and improve the utilization factor of the production line.