i am coming to taiyuan in this august 2017, what types of clothes i should keep with me ?

Hi, Arman. Taiyuan in summer is hot, maximun temperature at 31C (87.8F), and at night the temperature will fall to around 20C (68F). You are suggested to bring your summer clothes like short-sleeve shirts and a long-sleeve coat.
Life in Taiyuan is relatively affordable. A common dinner costs about CNY20. There's no need to worry about the consumption level there.