。
She has a high level of intelligence.
Literal
She [topic-は] intelligence [possessive-の] degree [subject-が] high.
知能の程度が高い is a formal, almost clinical way to describe someone as intelligent — 知能 ('intelligence/cognitive ability') and 程度 ('degree/level') are both academic terms. The structure [noun]の程度が高い/低い ('the degree of X is high/low') is typical of written assessments. In conversation, 頭がいい would be far more natural.