I wanted to fly Pudong shanghai Airport? I am in Yiwu, how I will reach there by train, easiest one.

You can take the last train the day before from Yiwu to Shanghai Hongqiao and then take the airport shuttle Line 1 to Pudong airport. You need to stay one night in Shanghai. Or you could take an early one from Yiwu to Shanghai, but if you want to arrive airport before 7am, you need to take a taxi, the cost would be high, maybe sround CNY150.