The invention discloses a hair loss preventing composition as well as anapplication into preparation ofing shampoo and conditioner products. The hair loss preventing composition is prepared from jackfruit peels, dalbergia cochinchinensis heartwood, rhizoma anemarrhenae, hairy waxmyrtle bark, balsamine, lucid ganoderma, citrus seeds, radix ginseng extract liquid, and zinc compound. The compositioncan effectively inhibit the activity of 5a-reductase in follicular cells and reduce the conversion of testosterone into dihydrotestosterone, so that the expression of transforming factors in the follicular cells can be reduced, the hair follicle cells can be retarded to enter a resting phase, and the hair loss problem can be prevented. The composition ofprovided by the invention can be applied toproducts contacting hair or scalp such as shampoo, conditioner, hair developing solution and the like. The addition amount of the hair loss preventing composition is 5 to 40 percent and preferably 8 to 30 percent.