12306 bus interval problem?

Generally speaking, the preferential interval of student tickets is determined according to the starting point and ending point filled in when booking tickets, not according to the route. Therefore, if the preferential interval on your student ticket is from Zhengzhou to Chengdu East, then whether you can use the student ticket for this journey from Zhengzhou to Xi 'an depends on whether this journey is within the interval from Zhengzhou to Chengdu East.

Specifically, you can log in to the Railway Customer Service Center (12306 official website) to check the station where your train passes, and see if the station you pass during the journey from Zhengzhou to Xi 'an is within the preferential interval from Zhengzhou to Chengdu East. If you have, you can buy a student ticket and enjoy a discount. If not, I suggest you buy the corresponding full-price ticket.

It should be noted that the preferential interval is relatively fixed, and the preferential interval of different trains and different time periods is not the same, which needs to be based on the specific ticket inquiry results.