The invention discloses a method for reducing the aluminum content in tea trees and tea. A black-green jade is machined into powder which is then dispersed in a soil cultivation layer at the root of a tea tree. Aluminum is an element which ranks only second to silicon in the earth crust and is widely spread in clay, feldspar and mica minerals, and vegetables, grains and tea also contain aluminum. The growth and disease resistance capabilities of the tea tree can be influenced when aluminum is insufficient. The aluminum is also a harmful element in the tea and is 200-1000mg/kg in content. The water-soluble aluminum in boiling tea reaches 148-601mg/kg. The aluminum content in old leaves in the tea tree is higher than that of tender leaves. When the content of aluminum ingested from daily tea drinking is more than 1mg specified in WHO (World Health Organization), osteoporosis and senile dementia are easily caused. So far, no method for reducing aluminum in tea trees exists. According to the method disclosed by the invention, an ultrafine jade powder solution containing soluble silica is applied to the soil at the root of the tea tree, so that soluble -SiO groups with negative charges are combined with Al<+3> in soil to form Al2O.Si2 which has low solubility and is used for fixing silicon in the soil, and therefore the absorption to the aluminum in the tea tree is reduced. The content of aluminum in the black tea or green tea as a finished product which is produced by using the method is reduced by 50 percent compared with that of aluminum in the black tea or green tea as a finished product which is produced without using the method.