Cash and cash are two different forms of foreign exchange assets held by China residents. Theoretically speaking, cash refers to foreign exchange deposits remitted from foreign banks to China, as well as international settlement documents such as foreign currency drafts, promissory notes and traveler's checks that banks can directly account for through electronic cost-effectiveness ratio. Cash refers to foreign currency cash held by domestic residents. Since foreign currency cannot circulate in China, it must circulate in the world. Therefore, in terms of circulation, your cash can be directly settled electronically, so the liquidity of cash is better than that of cash, which determines that the price is a little more expensive when banks buy cash. In addition, after receiving foreign currency cash, banks need some time to accumulate a certain amount before they can transport it and deposit it in foreign banks for allocation and use. Prior to this, banks that buy foreign banknotes have to bear certain interest losses; In the process of transporting cash and depositing it in foreign banks, there are freight, insurance and other expenses. Banks have to pass on these losses and expenses to customers who sell cash, so the price paid by banks for cash is lower than that of cash. From the above analysis, we can see that cash is more convenient for international settlement, but if you go abroad, your settlement is no longer inter-bank settlement. Cash is more convenient than cash, because cash can be used directly in foreign markets, and if you bring cash, you must go to the bank where you go to change it into cash before you can use it locally.