Tumor microenvironment (TME) is the environment around the tumor cells, consisting of extracellular matrix, nonmalignant stromal cells, and various types of immune cells (like macrophages, B and T lymphocytes). TME has been recurrently reported to play important roles in the progression of cancers. The mechanism study of TME may offer opportunities for targeted/immune therapies. However, how TME components impact the prognosis of cancer patients remains to be determined. In this study, we constructed a web server named OStme (Online consensus Survival analysis web server for Tumor MicroEnvironment components of pan-cancers) to analyze the association of cancer prognosis and various types of tumor-infiltrating cells (TICs), and to investigate the fraction variations of TICs across different stages/grades or variations along with metastasis/recurrence or variations regarding therapies. OStme is freely available at http://bioinfo.henu.edu.cn/Immune/Immune.html. OStme provides 12 types of survival terms (such as OS, DSS, and RFS), offers four analysis modules for cancer patient survival analysis, differential analysis per clinical characteristics (such as different stage, tumor versus normal), comprehensive TME fraction estimation, and the correlation between gene expression and TIC abundance of pan-cancers. We believe OStme will serve as a valuable resource and tool to systematically evaluate the impact of TICs on the prognosis, metastasis, recurrence, progression, and therapy of pan-cancers.