Abstract: In three different kinds of planting spacing of Poplar plantations, the input-output and financial maturity were studied and discussed in Yinan County, Shandong Province. In the plantation rotation, some input were finished once; and some input needed to be done every year. The former of the input were 2331.00 yuan/ha, and the ground preparation counted for 84%. The latter, the mean annual inputs were 253.21 yuan/ ha·a, and 75 percent of them were the expenses of the top application. The interest of the expenses and the net income were calculated. The annual input, annual income, annual net income and the mean annual net income were studied in the different kinds of planting spacing of Poplar plantations, and some incomes were showed with equations by statistical regression. Generally, we can get net income at third year after afforestation. The number of years for the quantity rotation were 6~10 years, and the highest mean annual income was 25.2521 m3/ha.a. The number of years for the financial rotation were 6~7 years, and the highest mean annual fixed net income was 6110.00yuan/ha·a. The financial maturity mainly depended on the input and planting spacing.