Background: There is no standard treatment for stage IV soft tissue tumor (STS) after the failure of Adriamycin-based chemotherapy. This opening, single-arm, multi-center phase II study (NCT03120846) assessed the efficacy and safety of Apatinib (YN968D1), a new tyrosine kinase inhibitor that targets VEGFR-2, for patients with stage IV soft tissue tumor after the failure of chemotherapy. Methods: Between September 2015 and February 2018, we recruited 42 patients with stage IV STS who had failed chemotherapy. The primary endpoint was progression-free survival (PFS), and the secondary endpoints were progression-free survival rate (PFR), objective response rate (ORR), and disease control rate (DCR) at week 12. Secondary endpoint was overall survival (OS). Treatment-related adverse effects (AEs) were evaluated. Results: Patients (19 men, 23 women; 14-83 years, average age: 47.67years) received 500 mg apatinib on Days 1–28 of 4-week cycles (median 5.7 cycles; range: 0–23 cycles). Median follow-up was 9 months (range: 1–28 months). We assessed 42 patients for AEs and 38 for efficacy. At 12 weeks, PFR was 70% and the ORR was 26.32% (10/38) and DCR was 86.84% (33/38). For the overall responses, the ORR was 23.68% (9/38) and DCR was 57.89% (22/38). The median PFS was 7.87 months and median OS was 17.55 months. The top AEs included hypertension (n= 18, 42.86%), hand-foot-skin reaction (n= 15, 35.71%), Apositia (13, 30.95%), and proteinuria (n= 11, 26.19%). No patients had grade-4 AEs. 11 (26.19%) had grade-3 AEs. 2 patients (4.76%) quit because the AE. Notably, the 26 patients (61.90%) who suffered hypertension, hand-foot-skin reaction or proteinuria had significantly longer OS than those without these AEs (20.94 vs. 8.93 months; Log Rank (Mantel-Cox) = 12.94, P= 0.0003). Conclusions: Apatinib is effective and well tolerated in patients with advanced soft tissue sarcomas. The adverse events hypertension, hand-foot-skin reaction, or proteinuria may indicate a favorable prognosis, representing a novel finding in STS patients. Clinical trial information: NCT03120846.