Background: The combination of anti-VEGF or anti-EGFR targeted drugs with chemotherapy is the standard first-line therapy for metastatic colorectal cancer (mCRC), and the followed maintenance treatment is an optional approach to balance the efficacy and toxicity. However, studies regarding the maintenance strategies based on antiangiogenic TKIs are limited currently. Anlotinib, a novel oral multi-target TKI which can inhibit both tumor angiogenesis and tumor cell proliferation simultaneously, substantially prolonged the PFS with manageable toxicity for refractory mCRC in the phase III ALTER0703 clinical trial. Here we report an update on the effectiveness and safety of anlotinib plus XELOX as first-line treatment followed by anlotinib monotherapy for mCRC. Methods: In this open label, single-arm, multicenter phase II clinical trial, 53 mCRC patients without prior systemic treated, aged 18-75 and an ECOG performance status of 0 or 1 were planned to recruit. Eligible patients received capecitabine (1000 mg/m², po, d1-14, q3w) and oxaliplatin (130 mg/m², iv, d1, q3w) plus anlotinib (10mg, po, d1̃14, q3w) treatment for 6 cycles. After 6 cycles of inducing therapy, patients would receive anlotinib (12mg, po, d1̃14, q3w) as maintenance therapy until disease progression or intolerable adverse events (AEs). The primary endpoint was PFS; Secondary endpoints included ORR, DCR, DOR and safety. Results: By the data analysis cutoff date of January 22, 2021, a total of 18 patients were enrolled, of which 12 patients were available for efficacy assessment. In best overall response assessment, there were 50.0% PR (6/12), 33.3% SD (4/12) and 16.7% PD (2/12). The ORR was 50.0% (95% CI, 21.1-78.9%) and DCR was 83.3% (95% CI, 51.5-97.9%). The longest duration of treatment was 8.8 months and the response was still ongoing. The median PFS was not reached. The most common treatment related adverse events (TRAEs) of any grade (≥20%) were leukopenia, hypertension, neutropenia, diarrhea, fatigue, hypertriglyceridemia. Grade 3/4 TRAEs included hypertension (22.2%), hypertriglyceridemia (11.1%), lipase elevated (11.1%) and neutropenia (5.6%). No grade 5 AEs occurred. Conclusions: The update results suggested that anlotinib combined with XELOX as first line regimen followed by anlotinib monotherapy showed promising anti-tumor activity and manageable safety for patients with mCRC. And the conclusions needed to be confirmed in trials continued subsequently. Clinical trial information: ChiCTR1900028417.