Abstract: In the light of solving the problems in barren hills afforestation，a study on the new technology of using chemical herbicide instead of burning cultivation to eradicate weeds，such like Imperata cylindrica，Saccharumarundinaceum and Miacanthusftoridulus，was conducted during 1981 to 1094．，Based Oil the experiments in about 200 small spots and the demonstrative tests in some larger areas，it has been proved that the following records are the optimum proportions of spraying herbicide solution．In the northern fores t areas of Fujian Province，application of 200g of effective Glyphosate plus lOOg of effective Krenite，or application of 300g of effective Glyphosate alone．For per mu(1mu=0．15ha)during June to September has Shown a good result and markable economic benefit．It has been confirmed that the technology opens a new way to the southern areas'barren hills afforestation without using the method of burning cultivation．