Study of B meson is of importance for fundamental particle’s physicists . The reason of this importance is that the B meson which owns long life , would just decay through weak interactions . So , important physical cases such as CP violation , inverse time violation and polarization asymmetry in decays , would be investigated by studying the decay of B meson . Also , since the exact values of matrix’s elements of CKM are determined only in weak interactions , investigating the decay of B meson is so useful . Also we could conclude that the experimental results are in good agreement with theoretical results by investigating the characteristics of the tensor meson . In fact , theoretical calculations on physical parameters of tensor mesons and comparison of their decay’s modes with scalar , semi-scalar , pseudo-scalar , vector and pseudo-vector mesons and also comparison of these calculations with experimental data , could give us important information about their natures . QCD sum rule is used for investigation of tensor’s characteristics . Lots of characteristics of hadrons are calculated by means of this rule and most of the times , these results are considerably in good agreement with the experimental results . QCD sum rule is a reliable and suitable tool for estimating of unknown hadron’s parameters . The aim of this study is investigating the semi-leptonic decays of B(Bs) meson in the framework of the three-point QCD sum rule . Considering the quark condensate contributions , the relevant form factors of these transitions are estimated . The branching ratios of these channel modes are also calculated at different values of the continuum thresholds of the tensor mesons and compared with the obtained data for other approaches . The main idea in this study is using meson’s current correlation function with the help of operator product expansion (OPE) .