hello! if i take flight from shanghai to another city and came back to suzhou again via shanghai, do me and my family needs to quarantine in suzhou, when came back?

You don't need to undergo quarantine if you have not been to medium or high-risk areas in Shanghai. You can check this article for the details: https://mp.weixin.qq.com/s/XKDnhV4tI2XGPF5zmK4vUg