Detector array target is a common device for measuring the distribution of laser spot, and the sampling panel of array target needs higher damage resistance under long-term high-power laser irradiation. In order to improve the damage resistance of the sampling panel, based on the finite element analysis software Ansys Workbench, from the perspective of thermal design, the research compares the temperature field and thermal stress of the protective sampling panels with different thicknesses, different heat pipe arrangements and different interface heat transfer coefficients under long-term high-power laser irradiation. The analysis results show that after adding a cross heat pipe arrangement, the withstand peak power density of the sampling panel with a thickness of 6 mm increases from 1470.9 W·cm^-2 to 3632.1 W·cm^-2when the laser irradiation lasts for 120 s. This simulation analysis provides effective theoretical and data support for the design of protective sampling panel for array target.