there are long distance busses from luoyang to pingyao or it's better to go by train?

There is no long distance buses between Luoyang and Pingyao and there is only one train from Luoyang to Pingyao.
But it sets off from Luoyang at about 20:00 in the evening and arrive in Pingyao at 06:15 the next day. In my opinion, the trains are better.

Yes, no direct long-distance bus from Luoyang to Pingyao is available. And only one train may help a little. I suggest you take a long-distance bus at Luoyang Bus Station to Taiyuan first. The buses are in service from 08:00 to 19:00. Upon arrival at Taiyuan, you can choose either the bus or the train to Pingyao easily.