We developed a new method to quantify the He atoms in the SiC/SiC Composites Irradiation Behaviour in Fusion Reactor Environment Conditions. We focus on the cavities measurements of the energy shift of the He K-edge of the electron energy loss spectrum. The method is based on mapping the density of He atoms inside the measured bubbles. Combining with the number density and the average diameter of the cavities, we are able to distinguish and estimate the amount of He atoms in the cavities and in the matrix, respectively. We found that small bubbles contain much higher density of He atoms than the larger ones. At irradiation temperature above 1000oC, all the He atoms are trapped inside the bubbles. On the contrary, it is not the case at the lower irradiation temperature.