Background: Anlotinib had significantly improved progress-free survival (PFS) and overall survival (OS) of advanced small cell lung cancer (SCLC) patients received at least two lines chemotherapy in the ALTER 1202 trial. Here, we reported the effect of anlotinib in advance SCLC patients relapsed within 3 months after second-line treatment. Methods: The ALTER 1202 was a randomized, double-blind phase 2 trial including patients with advanced SCLC that received at least two previous lines of chemotherapy. Eligible patients were randomized in a 2:1 ratio to receive either anlotinib or placebo until tumor progression or unacceptable toxicity. The subgroup analysis assessed the effect of anlotinib in patients relapsed within 3 months after second-line treatment. The primary outcome was PFS. The secondary outcomes were OS, objective response rate (ORR), disease control rate (DCR) and safety. This trial was registered with ClinicalTrials.gov, number NCT03059797. Results: In the ALTER1202 trial, 67 patients in anlotinib group and 34 patients in placebo group relapsed within 3 months after second-line treatment. Among them, the median PFS was 3.98 months (95% confidence interval [CI], 2.79 to 4.24) with anlotinib versus 0.72 months (95% CI, 0.69 to 0.82) with placebo (hazard ratio [HR], 0.14; 95% CI, 0.08 to 0.26; P < 0.0001). Meanwhile, anlotinib significantly prolonged OS compared with placebo (7.29 months [95% CI, 6.51 to 10.51] versus 4.37 months [95% CI, 2.33 to 6.47]; HR, 0.42 [95% CI, 0.23 to 0.74]; P = 0.0059) in patients relapsed within 3 months after second-line treatment. ORR was 4.48% (3 PR) for anlotinib and 2.94% (1 PR) for placebo (P = 0.708). DCR was 73.13% for anlotinib and 11.76% for placebo (P < 0.0001). The most common adverse events were hypertension (38.81%), anorexia (28.36%), fatigue (22.39%) and Elevation of alanine aminotransferase (17.91%). Conclusions: Anlotinib improved PFS and OS in advanced SCLC patients relapsed within 3 months after second-line treatment and was well tolerated.