Green bonds are creditor's rights and debt certificates issued to investors by issuers such as the government, financial institutions and industrial and commercial enterprises, which promise to pay interest at a certain interest rate and repay the principal according to the agreed conditions. The final investment of the raised funds should be green projects that meet the prescribed conditions. Green projects refer to those projects with sustainable climate and environment development.

The biggest difference between green bonds and ordinary bonds lies in their "green" attributes. In order to ensure that green bonds are really used in environmental protection and climate change mitigation projects, green bonds have higher transparency requirements than ordinary bonds. This requires that green bonds should disclose their green income and financing purposes to investors before and after issuance. If it is impossible to monitor whether bonds have environmental benefits, it will bring potential risks to investors with green investment preferences, and even "green washing" behaviors such as financing non-green projects in the name of green bonds may occur.

Compared with ordinary bonds, green bonds are special in four aspects: the use of funds raised by bonds, the evaluation and selection procedures of green projects, the tracking management of raised funds and the requirement of issuing relevant annual reports.