Abstract: The paper aims to solve the problem that some mature orchards of ten years and older have become inefficient in absorbing phosphorus fertilizers. In this study, the author took mature macadamia husk and plastic film mulching as the material, and investigated the utilization of phosphorus in hill macadamia orchard for two consecutive years. The results showed that, compared with the control, macadamia orchard mulched with macadamia husk and plastic film mulching could improve root biomass, and mulched with macadamia husk could significantly increase the generation rate of proteoid roots and fine root biomass, significantly increase the proportion of fine root in roots. With the extension of mulching time, the macadamia husk could significantly reduce the total phosphorus content of macadamia orchard soil, improve the phosphorus content of macadamia leaf, reduce the concentration of soil available phosphorus, and enhance the conversion efficiency of soil available phosphorus. Soil phosphorus content and soil available phosphorus content had an increasing trend under both plastic film mulching and the control, but the phosphorus content of leaves had a reducing tendency. Mulching with macadamia husk could significantly improve the rate of fruit and macadamia nut production, but the macadamia fruit set and yield were reduced by plastic film mulching. This research suggests that husk mulching should be a useful management approach in hill macadamia orchard.