This work studies the reliability of power electronic component in aeronautical environment to the ageing eect of the thermal cycling. The structure fatigue is sensitive to the process assembly conditions especially of the soldering process. To correclty evaluate the reliability of the power module, the identication of the solder behavior is one of the rst steps. Anand Model is here identied. Experimental test have to be established to evaluate the parameters of the law. A srt study is made to evaluate the indetiability of the law according to the dierent experimantal test. Then, the scatter of the parameters is evaluated in a context of time series. In the end, the scatter of the parameters is included in a nite element model to understand the inuence of this scatter on the evaluation of the number of cycle before failure.