This is a single arm, open-label, one center, dose escalation clinical study to determine the safety and efficacy of infusion of autologous T cells expressing CD19-redirected Chimeric Antigen Receptor (CD19 CAR T) in adult patients with relapsed or refractory CD19 positive B-cell lymphoma.

Inclusion Criteria:

1. CD19+ B cell lymphoma,verified by IHC or flow cytometry.
2. a prior history of at least two standard care of medication.
3. ineligible for allogeneic transplantation or relapsed after transplantation.
4. patients are 18 years older.
5. life expectancy > 3months.
6. ECOG ≤ 2.
7. satisfactory major organ functions: adequate heart function with LVEF≥50%; pulse oximetry of ≥ 90%; cockcroft-gault creatinine clearance≥40 ml/min; alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤3ULN; Bilirubin ≤2.0 mg/dl .
8. Blood: Hgb ≥ 80 g/L, ANC ≥ 1×10^9/L, PLT ≥ 50×10^9/L.
9. women of reproductive potential must have a negative pregnancy test. Male and female of reproductive potential must agree to use birth control during the study and one year post study.
10. measurable tumors.

Exclusion Criteria:

1. using immunosuppressive drugs or systemic steroids within one week of enrollment.
2. active infection.
3. HIV positive.
4. active hepatitis B virus infection or hepatitis C virus infection.
5. breastfeeding or pregnant women.
6. patients refuse to practice birth control during study and one year post study.
7. patients with a prior history of other malignances will be excluded from this study, but patients who have been cured from skin basal cell carcinoma or cervical cancer, or who have had their tumors removed by surgical resection but without further therapies and have more than 5 years of progression-free survival, can be included into the study.
8. currently enrolled in other study.
9. patients, in the opinion of investigators, may not be eligible or are not able to comply with the study.