Well, Shantou is in Guangdong and Pinghu is in Zhejiang, so the journey is far. Firstly, you could take flight from Shantou to Shanghai Hongqiao Airport. The flights could searched at https://www.travelchinaguide.com/china-flights/

Arrive at Hongqiao Airport, you could take bus 806 or 938 to reach Hongqiaolu Station where you could take the Shanghai subway Line 3 to Shanghai South Railway Station. The Shanghai South Bus Station is just close to the Railway Station. There are 15 buses departing here to Pinghu City from 07:27 to 18:40. The 117-kilometer's journey takes 1.5 hours and 38yuan.

From Pinghu to Yiwu, firstly you could take a bus from Pinghu South Bus Station to Jiaxing West Bus Station. Out the bus station, take city-bus No.33 to arrive at Jiaxing Railway Station where there are 37 scheduled trains running to Yiwu City everyday in 2 hours. For the train information, see: https://www.travelchinaguide.com/china-trains/

Hi, I know there are two buses to Yiwu from Pinghu South Station respectively at 08:30 and 10:00.