Abstract: Objective: The purpose of this paper was to explore the effects of cultivating Pleurotus ostreatus with areca nut processing by-products as alternative materials on the growth, fruiting body nutrients and substance transformation of Pleurotus ostreatus. Method: Taking Pleurotus ostreatus No.1 as the test strain and taking the mycelium growth rate and growth potential as the index, the effects of water content, particle size and proportion of substitute materials on mycelium growth stage of areca nut by-product culture material were studied. The effects of substitute cultivation under different conditions on the development of Pleurotus ostreatus fruiting body and the material transformation law of polyphenols, flavonoids, cellulose and hemicellulose of areca nut processing by-products in Pleurotus ostreatus cultivation were studied. Results: When Pleurotus ostreatus was cultivated with areca nut processing by-products as alternative materials, Pleurotus ostreatus could grow normally on different culture materials. Using areca nut core and areca nut pedicle as substitutes, the optimum water content in the culture medium was 65% and 70% respectively, and the optimum particle size was 0.15~0.3 cm. In the mushroom production test, among the four Pleurotus ostreatus fruiting bodies cultivated with different proportions, the contents of polyphenols and flavonoids in the 50% replacement group of areca nut core were the highest, reaching 51.05 mg/g and 0.42 mg/g respectively, which increased by 53.21% and 133% compared with the control group. The content of polysaccharide in areca nut core 30% substitution group was the highest, up to 42.01%, which was 77.10% higher than that in the control group. After cultivation, the content of flavonoids in the culture medium of areca nut pedicle decreased the most, which was 86.70%. The group with the largest decrease in polyphenol content was areca nut core 50% substitution group, which was 46.99%. Conclusion: This study provides a theoretical basis for the areca nut processing by-products substitute cultivation of Pleurotus ostreatus, and also provides a new way for the comprehensive utilization of areca nut by-products.