P-Hydroxylcinnamaldehyde (CMSP) was firstly isolated from Chinese medicine Cochinchinnamomordica seed (CMS) by our team and has been verified to have growth-inhibiting abilities in malignant tumors including esophageal squamous cell carcinoma (ESCC). However, the detailed mechanism of its function is still unclear. Tumor-associated macrophages (TAMs) are an essential component of the tumor microenvironment (TME), playing important roles in tumor growth, metastasis, angiogenesis, and epithelial-mesenchymal transition (EMT). In the present study, we found that the percentage of M1-like macrophages was significantly increased in TME of ESCC cell derived xenograft tumor model after CMSP treatment, while the ratios of other immune cells showed relatively low variation. To confirm these results, we further examined the effect of CMSP on macro-phage polarization in vitro. The results revealed that CMSP also could induce phorbol-12-myristate-13-acetate (PMA)-induced M0 macrophages from THP-1 and mouse peritoneal macrophages toward the M1-like macro-phages. Furthermore, CMSP could exert anti-tumor effect through TAMs in vitro co-culture model, in addition, the growth inhibition effect of CMSP was partly abolished in macrophage depletion model. To determine the potential pathway of CMSP induced polarization, we used quantitative proteomics (label-free) technology to explore the proteomic changes under CMSP treatment. The results revealed that immune-activating protein and M1 macrophage biomarkers were significantly increased after CMSP treatment. More importantly, CMSP stim-ulated pathways related to M1 macrophage polarization, such as the NF-kappa B signaling pathway and Toll-like receptor pathway, indicating that CMSP might induce M1-type macrophage polarization through these path-ways. In conclusion, CMSP can regulate immune microenvironment in vivo and induce TAM polarization toward the M1 type by promoting proteomic changes, and exert anti-tumor effect through TAMs.