I paid social security in Jiangsu and then stopped, and then I paid it in Fujian. Can the two social security systems be merged?

Well, your social security has several components, including medical insurance. Because you change provinces and stop paying for three months in Guangdong Province, the medical insurance will automatically expire. That is to say, hospitals in Guangdong can't enjoy insurance compensation when they are sick, but they can also enjoy Jiangsu's medical insurance as long as they work in Jiangsu for more than two months, so the medical insurance has little impact. The second is the provident fund. The provident fund part is to buy a house in Guangdong now, and you can't enjoy the provident fund loan. However, if you buy a house in Jiangsu, you can enjoy the low-interest provident fund loan as long as you pay 12 months in Jiangsu. However, the money in the provident fund account you paid in Guangdong can provide the previous company's resignation certificate, and you can take your labor contract in Jiangsu to withdraw cash from the Guangdong Provident Fund Center. Another trouble is that your old-age insurance needs to be accumulated in accordance with state regulations. The more years of payment, the more pensions you receive. Because Guangdong and Jiangsu are not connected with each other, when you need to receive a pension when you retire, you need to transfer the pension paid by one of the provinces to another province and merge. But don't worry, many people will work in three or four cities at the same time, but in fact, the pension before retirement will not affect you. The trouble is that when you need a pension after retirement, you need to put several copies.

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