• Understand and voluntarily sign the informed consent form;

• Age ≥ 18 years old at the time of screening, regardless of gender;

• Patients with diffuse large B-cell lymphoma who have been diagnosed as CD19 positive by histopathology and/or cytology, but have failed standard treatment in the early stage, and currently lack effective treatment methods for recurrent or refractory CD19 positive.

• The regulations for the past treatment status of research participants are as follows (meeting at least one of them): 1.At least after sufficient second-line treatment (CD20 positive individuals must have already used sufficient amounts of CD20 targeted drugs and anthracycline drugs), recurrence, no remission, or progression; In the first two lines of treatment, if the optimal therapeutic effect is SD, then the line of treatment must have completed 2 cycles;2.Recurrence, unrelieved, or progression after autologous hematopoietic stem cell transplantation;

• According to the 2023 NCCN Lymphoma Treatment Guidelines and the 4th edition of the WHO Lymphatic Tissue Tumor Classification in 2016, the following types were included in this trial:Diffuse large B-cell lymphoma (DLBCL) non-specific (DLBCL-NOS)；Transforming follicular lymphoma (tFL)；High grade B-cell lymphoma (HGBL) with MYC, BCL2, and/or BCL6 rearrangement；High grade B-cell lymphoma, non-specific (HGBL-NOS)；Primary mediastinal large B-cell lymphoma (PMBL)；Grade 3b follicular lymphoma (FL3b);

• Expected survival time ≥ 12 weeks;

• There are measurable target lesions in imaging: the length and diameter of lesions in lymph nodes ≥ 15mm, or extranodal lesions\>10mm (according to Lugano2014 standard); Lesions that have received radiotherapy in the past are considered measurable only when there is clear progress after completing radiotherapy;

• During screening, laboratory inspections must meet the following requirements:Neutrophil count ≥ 1.0 × 10\^9/L;Lymphocyte count ≥ 0.3 × 10\^9/L; Hemoglobin ≥ 70 g/L;Platelets ≥ 50 × 10\^9/L;Total serum bilirubin ≤ 2.0 × Upper limit of normal value (ULN);Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤ 2.5 × ULN;Creatinine\<1.5 × ULN and endogenous creatinine clearance rate ≥ 60 mL/min (creatinine clearance rate Cockcroft Fault method: male creatinine clearance rate=\[(140 age) × Weight (kg)\]/\[0.818 × Creatinine（ μ Mol/L)\]; Female creatinine clearance rate=\[(140 age) × Body weight (kg) × 0.85\]/\[0.818 × Creatinine（ μ Mol/L)\].

• The lung function is good, and the blood oxygen saturation of the fingertip pulse under non oxygen inhalation is ≥ 92%;

• The Eastern Oncology Collaborative Group (ECOG) physical fitness score is 0 or 1;

• Head MRI shows no central nervous system lymphoma;

• Cardiac ultrasound shows left ventricular ejection fraction ≥ 50%; No clinically significant abnormal electrocardiogram findings; No clinically significant pericardial or pleural effusion;

• Adequate venous access (for single collection) and no other contraindications for blood cell separation;

• The screening period blood pregnancy test for female participants of childbearing age must be negative