The printing method of paper can choose single-sided printing or double-sided printing according to specific needs. Single-sided printing means that each page has only the front side, which is suitable for both sides of the paper, such as cover, abstract, catalogue, references and so on. These parts usually do not need to be printed on both sides, because they will not affect the continuity of the text. Double-sided printing means that each page includes both sides, which can save paper and protect the environment. Text parts often require double-sided printing, because this is the core content of paper, and double-sided printing can reduce the waste of printed materials. Therefore, the printing method of paper can choose single-sided printing or double-sided printing according to the specific situation.