"女时装模特儿" can be translated into English as "female fashion model" or simply "fashion model (female)"（though the latter is less commonly phrased that way in a standalone context; "female fashion model" is more natural and direct）.
In more concise or colloquial contexts, you might also hear just "model" when the gender is implied or known from context, but to specifically emphasize "female," "female fashion model" is the clear and accurate choice.