"箱门尺寸" can be translated as "door dimensions of the box/container" or more concisely as "box/container door size" depending on the context.
If you're referring to the specific measurements of the door on a box, container, or enclosure, "door dimensions of the box/container" would be precise.
For a more general or colloquial expression, "box/container door size" is sufficient and commonly understood.