Background: Colorectal cancer (CRC) is the third most common malignancy worldwide. Matrine can act as a potential antitumor drug, and its antitumor activities have been tested in various cancers, including CRC. However, the effect of matrine and the related mechanisms on CRC cells remains poorly defined. Materials and Methods: CRC cells were treated with different concentrations of matrine, and then MTT, flow cytometric, and transwell assays were used to assess cell proliferation, apoptosis, invasion, and migration. MiR-10b-5p and Phosphatase and tensin homolog (PTEN) expression levels were measured by quantitative real-time polymerase chain reaction and Western blot assay. The binding interaction of miR-10b-5p and PTEN were predicted by TargetScan and verified by a dual-luciferase reporter and RIP assay. The effect of matrine, miR-10b-5p, and PTEN on CRC cell proliferation, apoptosis, migration, and invasion was detected by MTT, flow cytometric, and transwell assays severally. Results: Matrine notably restrained proliferation, invasion, and migration and boosted apoptosis of CRC cells, as well as downregulated miR-10b-5p expression and upregulated PTEN protein level. PTEN was a direct target of miR-10b-5p in CRC cells. MiR-10b-5p knockdown and matrine treatment inhibited cell proliferation, migration, and invasion and induced apoptosis, and reintroduction of si-PTEN partly regained the inhibiting effect. Besides, MiR-10b-5p knockdown and matrine treatment repressed CRC growth in vivo. Conclusion: Matrine could suppress proliferation, migration, and invasion and induce apoptosis of CRC cells via the miR-10b/PTEN pathway, providing the potential molecular mechanism of matrine in blocking CRC progression.