National debt is a kind of bond issued by the national government to make up the fiscal deficit and balance the fiscal revenue and expenditure.

In modern economy, the state issues bonds mainly as a fiscal policy to regulate the economy.

Treasury bonds are generally long-term, with high security and profitability, higher interest rate than time deposits in the same period, and strong investment and liquidity. Therefore, developing the national debt market is an important part of the capital market. It is convenient for the country to raise funds.