In order to study director arrangement of the cholesteric liquid crystals layer with planar texture (CLCPT) in parallel anchored (PA) and orthogonal anchored (OA) cells with temperature changes, two samples of CLCPT in PA and OA cells were prepared respectively. A fully leaky guide mode structure consisting of two trapezoidal low refractive index prisms, the refractive index matching liquids and one CLCPT cell was constructed. The method of fully leaky optical guided wave (FLOGW) was introduced to measure the experimental curve of reflectivity Rss with inner angle (the incident angles of the test light incident on the CLCPT layer) at different temperatures. The temperature dependence of the theoretical curves revealed by simulations based on elastic theory of liquid crystal and multi-layer theory was in agreement with the experiment result, and the characteristics of CLCPT director arrangement with temperature changes in PA and OA cells were accurately analyzed. In addition, the actual birefractive index values of cholesteric liquid crystal (CLC) at different temperatures were measured by the control variable method.