This study evaluates the safety and efficacy of Befotertinib combined with Bevacizumab as a first-line treatment for patients with EGFR mutation-positive advanced non-small cell lung cancer (NSCLC) accompanied by brain or leptomeningeal metastases. It is a single-arm, open-label, prospective Phase II clinical trial aiming to explore the potential benefits of this combination therapy in improving intracranial progression-free survival (iPFS) and overall survival (OS). Patients will receive Befotertinib daily and Bevacizumab every three weeks until disease progression, intolerable toxicity, or withdrawal of consent. The study seeks to address the unmet need for effective treatments in this challenging patient population.