In recent years, the green synthesis of nanoparticles has attracted considerable attention because these methods are eco-friendly, cheap, and simple. In this study, copper nanoparticles were synthesized using Prunus mahaleb L. extract. Synthesized Cu nanoparticles were characterized by UV-Visible, XRD, FE-SEM, and EDX methods. The analysis showed that the shape of nanoparticles was almost spherical and the max abundance distribution of particle size was between 20 to 30 nm. Afterward, the biological properties of CuNPs were determined using antioxidant, anticancer, anti-mutagenicity, and antimicrobial. In the DPPH test, CuNPs showed low antioxidant activity (15.90 % inhibition). The anticancer activity of CuNPs was determined using brine shrimp lethality assay. The results showed that CuNPs had high potential cytotoxic activity (LC₅₀ = 3.6 µg/mL). The Ames test results showed that CuNPs are not mutagenic and have high anti-mutagenic properties with a percent mutagenicity inhibition of more than 40%. However, CuNPs had the most effect on gram-positive bacteria. Also, the calcium alginate beads of Cu nanocomposites had lower antimicrobial activity than CuNPs. The results showed that the extract of different P. mahaleb parts could be used to synthesize CuNPs. Due to the high cytotoxic and anticancer activities of these nanoparticles, they can be used as drugs to treat diseases, especially cancers.