Background: Pancreatic cancer is a malignant tumor with limited therapeutic strategies and poor prognosis. About 60% of the patients have metastasis disease at time of diagnosis and lose the opportunity for surgery. Thus, therapy based on drugs becomes a vital part in pancreatic cancer. In 2013, MPACT showed that albumin-bound paclitaxel combined with gemcitabine in the treatment of metastatic pancreatic cancer could increase the mOS from 6.6 months to 8.7 months (HR = 0.72, 95% CI: 0.62-0.83; P < 0.001). Nowadays, the immunosuppressive checkpoint inhibitors acting on PD-1/PD-L1 pathway have shown a significant efficacy in enhancing tumor immune surveillance and anti-tumor immune response. In 2018, two studies reported in ASCO showed the preliminary efficacy of albumin paclitaxel, gemcitabine and PD-1 inhibitor in the treatment of advanced pancreatic cancer. Among patients who have not received treatment before, the disease control rate was even up to 100%. Therefore, this study will further explore the domestic PD-1 antibody combined with albumin-bound paclitaxel and gemcitabine as the first-line treatment of advanced pancreatic cancer among Chinese pancreatic cancer patients. Methods: This is a prospective, single-armed, exploratory, investigator initiated trial to explore the efficacy and safety of PD-1 antibody combined with albumin-bound paclitaxel and gemcitabine as first-line treatment of metastatic pancreatic cancer. This study is, to our knowledge, the first one to test the efficacy and safety of PD-1 antibody on metastatic pancreatic cancer patients among Chinese population. Survival index is median survival estimated by Kaplan-Meier and draw the survival curve. The response rate was compared by χ 2 test / Fisher test. All primary and secondary outcomes will be analyzed on the full analysis set. PD-1 antibody, 200mg, D1 administration; paclitaxel (albumin binding type), 125mg/m2, D1, 8 days administration; gemcitabine, 1000mg/m2, D1, 8 days administration, every 21 days as a cycle and PD-1 antibody (200mg, D1, every 21 days) single drug maintenance treatment is given after the completion of 6 cycle chemotherapy. Major eligibility criteria is that each participant must have metastatic pancreatic cancer confirmed by histology or cytology and has never received systemic anti-tumor therapy before. So far, 11 of planned 20 patients have been enrolled. Clinical trial information: NCT04181645.