I used to be insured in Nanjing, but now my work unit is in Jiangning. Can I directly participate in Jiangning insurance without transferring social security?

No need to turn. At present, in Nanjing's big social security system, we can see Jiangning's employees' participation in pension and medical care. In the future, Nanjing's social security and Jiangning will merge, and there is no need to transfer at present. The years paid in Jiangning can be calculated cumulatively with the years paid in Nanjing, and there will be no influence.

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