I used to buy my own social security in my hometown. Do I need to pay social security when I work in a different place in this province? Or ignore it, the system will automatically hand it over.

There is no need to transfer back to my hometown. According to the Administrative Measures for the Transfer and Continuation of Social Security Relations, which was implemented on 20 10, if you leave your job in a place, you can ask the unit to handle the local social security relationship transfer form for you, get back your own endowment insurance manual, go to a new unit (including a new unit in a different place), and then handle the social security relationship transfer and continuance at the local social security center with the social security relationship transfer form and endowment insurance manual.

Further reading: How to buy insurance, which is good, and teach you how to avoid these "pits" of insurance.