I would like to ask whether the social security in Shanghai should be paid 15 years, which means continuous payment 15 years or cumulative payment 15 years?

You only need to pay 15 years. Shanghai social security can receive basic pension on a monthly basis after the accumulated payment period is 15 years. Shanghai's basic pension should be collected according to household registration. The basic pension relationship is in the household registration place, and you can receive pension benefits in the household registration place.

You have paid in many places, but only in one place for 10 years, then you will receive pension benefits in the place where you paid 10 years. If you have paid in many places and paid in many places for 10 years, you will receive pension benefits in the last place where you paid 10 years. I have paid it in many places, but I didn't pay it in all places in 10, so I still have to go back to my domicile to receive pension benefits.