For avoiding the invalid acceleration experiments caused by the changes of the failure mechanism, the relationship of the failure mechanism consistency and the parameters of degradation data distribution in the early stage under different accelerated stress levels has been derived. Conditions for judging the failure mechanism consistency are also given as follows: firstly, the shape parameters of failure distribution has a uniform distribution mi=m, i=1,2,3,···; secondly, the dimension parameter ηi follows the equation ηi=AFi·η. A method to rapidly discriminate the consistency of failure mechanism under different experimental stresses in the early stage was obtained, and the invalid acceleration experiments caused by the changes of the failure mechanism could be avoided. Finally, theoretical degenerate data in the early stage of the accelerated test and the initial degenerate data of the MCM thick-film resistor were used for estimating, Weibull distribution parameter, and the consistency of failure mechanism degradation was also judged.