Corrosion under insulation (CUI) is a major potential threat in the petroleum and chemical industries. In the industry, a wide variety of insulation thickens are available in coated pipes. Conventional probes use adjusted power to detect different thickens of insulation, increasing the detection difficulty. In order to adapt to the change of the thickness of insulation layer, a model of corrosion under insulation layer based on focused emission array is studied. A multi-probe array is used to adjust the thickness of different types of insulation layer by adjusting the deviation Angle between the multiple probes. The difference of thermal insulation thickness between single probe and multi-array probe is compared, and the diversity of thermal insulation thickness variation is verified by focusing emission array.