This is a single-center, open, single-arm study exploring the efficacy and safety of fruquintinib combined with FOLFIRI/FOLFOX in the treatment of RAS-mutated metastatic colorectal cancer (mCRC) who failed standard therapy. Patients will receive fruquinitinib combined with chemotherapy (FOLFOX or FOLFIRI regimens), which depend on the previous chemotherapy regimen (chemotherapy switch).