In this work, we prepared an in situ gel-forming composite drug delivery system (DDS) to treat colorectal peritoneal carcinomatosis. The composite DDS was based on curcumin loaded polymeric micelles (Cur-M) and thermosensitive hydrogel. Cur-M had a particle size of 27.1 ± 1.3 nm with polydisperse index of 0.149 ± 0.017, and the drug loading and encapsulation efficiency of Cur-M were 14.82 ± 0.07 and 98.83 ± 0.45%, respectively. The prepared Cur-M in thermosensitive hydrogel system (Cur-H) was a free-flowing sol at ambient temperature, and converted into non-flowing gel at body temperature, serving as a drug depot. In vitro drug release behavior suggested that Cur-H and Cur-M could release Cur in an extent period, and Cur-H showed a slower cumulative release rate. In addition, compared with free Cur, Cur-M showed higher cytotoxicity and apoptotic induction efficiency. Furthermore, colorectal peritoneal carcinomatosis mouse model was used to evaluate the anti-tumor activity of Cur-H, and the results suggested that Cur-H could inhibit tumor growth and metastasis, and prolonged survival of tumor-bearing mice. Immunohistochemical and immunofluorescent staining of tumor tissues in each group were conducted. The results demonstrated that tumors in Cur-H group showed lower proliferation activity, more apoptotic cells, and fewer microvessels. Besides, pharmacokinetic studies of Cur-H and Cur-M by intraperitoneal administration were performed. Compared with Cur-M, Cur-H showed a higher AUC and longer t½. Thus, the above results suggested that Cur-H may have potential applications in colorectal peritoneal carcinomatosis.