“客户基础”常见的英文表达是 customer base。
例句：
The company has a large and stable customer base.（该公司拥有庞大且稳定的客户基础。 ）
Building a strong customer base is crucial for the long-term success of any business.（建立一个强大的客户基础对任何企业的长期成功都至关重要。 ）