how many hours by speed train from shanghai to zhengzhou?

You can get to Zhengzhou from Hongqiao Railway Station by a bullet train. It takes around 7 hours on the way.
The price for a flight varies a lot at different times. Generally speaking, the price fluctuates in CNY500~800 for the single trip.

Thx alot
But i want from shanghai to zhengzhou....

Oh, by bullet train, the return way takes almost the same - around 7 hours. It is hard to tell the exact cost of airplane without your travel date, but the fare is CNY600-900 recently for your reference. For the details, you can search the Flight Page of the website to get.