Development of natural wood preservatives for the protection of wood against to the wood degrading agencies. Present investigation was designed to determine the feasibility of natural plant extracts on wood degradation and chemical constitute after decay test of Pinus roxburghii wood. During the study two plants species were selected for the wood preservation in this contest plant extract was extract with the help of two different solvent methanol and petroleum ether from the Acorus calamus and Parthenium hysterophorus. Wood samples treated with extract at various concentration (0.25%, 0.50%, 1.00%, 1.5%, 2%) and one control and exposed with white fungi (Trametes versicolor) for the three months. Treated wood samples show minimum (13.46%) degradation with methanol extract of P. hysterophorus and 13.63% degradation with petroleum ether of A. calamus treated wood sample and maximum degradation was noticed in untreated wood samples, degradation of wood sample was increase with decrease the plant extract concentration. At the same chemical properties of wood sample were also examine after decay test and find out that the maximum clod and hot water soluble extractives and alcohol benzene soluble extractives, lignin and holocellulose content were notice maximum in treated wood sample and decrease with decreasing in the plant extract concentration. Novelty of the study is selected plats show the antifungal property against to the fungi. It is help full in the wood preservation without effect the environmental health and human being.