As we all aware of it, there exist plenty of natural phenomenon which their thermodynamic behavior as a result of nonextensivity is not justifiable by common Boltzman-Gi Statistical Mechanics. In this dissertation, the amount of energy fluctuation for two models ideal gas and harmonic oscillator, in the second and forth version of Tsallis statistical Mechanics has been considered. The results demonstrate that energy fluctuation in the second method of Tsallis Statistical Mechanics is going to be controlled by three terms, in which, the first term is in relation with heat capacity where in Tsallis and Boltzman-Gi Statistical Mechanics will be appeared with various coefficients according to the type of Statistical Mechanics and definition of average energy. The second and third terms will be under control by three factors, incoming nonextensivity to the entropy function, weighting of the probability function, and unnormalized of the energy constraint. Fluctuation analysis in the fourth method of Tsallis Statistical Mechanics, seems to be the most perfect method of this Statistical Mechanics, shows that the amount of energy fluctuation in the range of qs less than unity is always smaller then Boltzman-Gi and on the other hand for qs larger than unity, is larger than Boltzman-Gi all the times. Indeed, when the number of accessible states of system is more than Boltzman-Gi Statistics,, relative fluctuation of energy would be further and in contrary when the number of accessible states is fewer than Boltzman-Gi, the fluctuation will be fewer, too. It is praiseworthy to mention that, the amount of energy fluctuation in the second method in the case of harmonic oscillator while , would be less than Boltzman-Gi due to the few number of accessibility states. Nevertheless, energy fluctuation regarding an ideal gas thanks to abundance of number of accessible states in almost all qs, except that q which is a little less than unity, is more than Boltzman-Gi Statistics. Generally speaking, extensive number of energy fluctuations and consequently fluctuation of quantities is one of the main drawbacks of the second Tsallis Statistical Mechanics. Actually, in this method, we cannot consider the average mechanical property of the system as equal as the thermodynamic property, in other words, the average of energy lacks physical meaning.