• Age at least 18 years old.

• The Eastern Cancer Organization Collaboration Group (ECOG) had a physical fitness score of 0 to 3, and had not worsened in the previous 2 weeks, with a minimum expected survival of 12 weeks.

• NSCLC confirmed by histology or cytology, positive cerebrospinal fluid cytology, and combined with central nervous system function and brain imaging findings, diagnosed as NSCLC with meningeal metastasis (including advanced patients who had relapsed or were initially diagnosed after previous surgical treatment; GPA is recommended for grading and typing in the diagnosis of meningeal metastasis from lung cancer).

• Tumor tissue samples or blood samples were tested and confirmed as EGFR sensitive mutations (including exon 19 deletion or L858R, both alone or coexisting with other EGFR site mutations). The first choice is to submit tumor tissue for examination; If the tumor tissue is inaccessible or the subject is not eligible for tissue biopsy, a blood sample may be sent for examination.

• The patient has implanted an Ommaya capsule;

• CT examination of clinical symptom areas (spine and/or brain) and/or head within the past 3 months to rule out contraindications to cerebrospinal fluid examination;

• The subjects agreed to provide two cerebrospinal fluid samples (before treatment and within one week after disease progression) for genetic testing;

• Women of childbearing age need to take appropriate contraceptive measures and should not breastfeed three months after screening and discontinuing study treatment. Before starting administration, the pregnancy test was negative, or one of the following criteria was met to demonstrate that there was no risk of pregnancy:

‣ Postmenopause is defined as amenorrhea at least 12 months after age greater than 50 years and cessation of all exogenous hormone replacement therapy.

⁃ Women younger than 50 years of age may also be considered postmenopausal if they have amenorrhea for 12 months or more after stopping all exogenous hormone therapy, and their luteinizing hormone (LH) and follicle stimulating hormone (FSH) levels are within the laboratory postmenopausal reference values.

⁃ Have undergone irreversible sterilization surgery, including hysterectomy, bilateral ovariectomy, or bilateral salpingectomy, except for bilateral tubal ligation.

• Male subjects should use barrier contraception (i.e., condoms) three months after screening and discontinuation of study treatment.

• The subject voluntarily participated and signed an informed consent form in writing.