A prospective, open, single-arm clinical study to evaluate the efficacy and safety of jinyouli（PEG-rhG-CSF） in the first-line treatment of advanced pancreatic cancer with nab-paclitaxel combined with S-1.Chemotherapy regimen: (1) chemotherapy: nab-paclitaxel, 260mg/m2, intravenous infusion for 30 minutes, D1, Q3W. S-1, 80-120mg, PO BID, D1-14, Q3W. (2) patients who met the eligibility criteria were given jinyouli injections 24 hours after the end of intravenous infusion of nab-paclitaxel during the treatment period.

Inclusion Criteria:

• Age ≥ 18 years, ≤70 years;
• Patients with Advanced Pancreatic Cancer diagnosed by histopathology，the expected survival time is more than 3 months;
• Neutropenia of ≥2 degree occurred with the nab-paclitaxel + S-1 regimen in the previous cycle.
• KPS score≥70;
• The peripheral blood routine of the patients was normal: ANC ≥ 2.0x10^9/L, platelet count ≥ 90x10^9/L, HB ≥ 80g/L before enrollment, and there was no bleeding tendency;
• Patients volunteered to participate in the trial, signed a written informed consent, willing to be followed up.

Exclusion Criteria:

• There are uncontrollable infections at the moment or systemic antibiotic treatment within 72 h of chemotherapy；
• Any abnormal bone marrow hyperplasia and other abnormal hematopoietic function；
• Patients who had received bone marrow or hematopoietic stem cell transplantation within 3 months；
• Patients with other malignancies that have not been cured or with brain metastases；
• Total bilirubin(TBIL), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) >2.5 ULN, or >5 ULN if there is liver metastasis;
• Serum creatinine (Cr) exceeded the upper limit of normal value；
• Allergic to this product or other biological products derived from genetically engineered escherichia coli；
• Suffering from a mental or nervous system disorder, without self-awareness or coordination；
• Patients expected to have a short survival or have difficulty tolerating chemotherapy；
• Pregnant or lactating female patients；
• Patients using other drugs of the same category or in clinical trials of other drugs；
• Not suitable for participation at investigators' discretion.