This is a single-arm, open-label, single-center, phase I study. The primary objective is to evaluate the safety of CD7 Chimeric Antigen Receptor-T(CAR-T) therapy for patients with CD7-positive relapsed or refractory natural killer/T cell lymphoma, and to evaluate the pharmacokinetics of CD7 CAR-T in patients。

Inclusion Criteria:

1. Age 3-70
2. Diagnosis of r/r NK/T lymphoma.
3. CD7 positive expression
4. Bone marrow lymphoblasts ≥5% by morphologic evaluation at screening
5. Creatinine clearance (as estimated by Cockcroft Gault) ≥ 60 mL/min, Serum alanine aminotransferase(ALT)/aspartate aminotransferase(AST) < 3×upper limit of normal, Total bilirubin < 1.5×upper limit of normal or ≤1.5mg/dl
6. Left ventricular ejection fraction ≥ 50% .
7. Baseline oxygen saturation ≥ 92% on room air.
8. Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 2.
9. The estimated survival time is more than 3 months.
10. Subjects or their legal guardians volunteer to participate in the study and sign the informed consent.

Exclusion Criteria:

1. Subjects with concomitant genetic syndromes associated with bone marrow failure states.
2. Isolated extramedullary lesions
3. Subjects with some cardiac conditions will be excluded.
4. With uncontrolled active central nervous system leukemia (CNSL), cerebrospinal fluid grade Central Nervous System3(CNS3).
5. History of traumatic brain injury, consciousness disturbance, epilepsy, cerebrovascular ischemia, and cerebrovascular hemorrhagic disease, which might compromise the ability of the subject to compliance with the obligations under the protocol.
6. History of malignancy other than non-melanoma skin cancer or carcinoma.
7. Primary immune deficiency.
8. Presence of uncontrolled infections.
9. Subjects with some anticancer therapy before CAR-T infusion will be excluded.
10. Active uncontrolled acute infections.
11. Known history of infection with human immunodeficiency virus (HIV); active or latent hepatitis B, hepatitis C and syphilis.
12. Subjects who are receiving systemic steroid therapy prior to screening.