LHCb合作组以及将来的Belle II、SuperB合作组对B介子稀有衰变过程的精确测量，为研究CP破坏和寻找新物理提供了极好题材。在标准模型中，B介子稀有衰变过程由味道改变中性流传递，在圈图水平出现，分支比小，对新物理敏感。新物理同样在圈图水平上体现自己存在，稀有过程是理想研究题材。光锥QCD求和规则产生于传统QCD求和规则和硬遍举过程的结合，是计算形状因子和强耦合常数的强有力工具。我们以轻介子光锥波函数作为基本参数，利用光锥QCD求和规则研究B介子到标量、赝标量、矢量、轴矢量轻介子的形状因子，系统计算扭度为二、三光锥波函数项的单圈辐射修正；并以B介子光锥波函数作为基本参数，利用B介子光锥QCD求和规则研究B介子到标量、赝标量、矢量、轴矢量轻(重)介子的形状因子，系统计算两粒子B介子光锥波函数项的单圈辐射修正。我们详细研究B介子半轻子衰变和辐射衰变，抽取CKM矩阵元，间接寻找新物理。

The LHCb collaboration and the Belle II, SuperB collaborations in the future can measure the rare B-decays with high precision, which provides excellent subjects in studying the CP violations and searching for new physics. In the standard model, the rare B-decays take place through the flavor-changing neutral currents and appear at the loop-level, therefore the branching fractions are small and sensitive to new physics. As the new physics also show up at the loop-level, the rare B-decays are ideal subjects in searching for new physics. The Light-cone QCD sum rules, which originates from the combination of the traditional QCD sum rules and hard exclusive processes, is a powerful theoretical tool in studying the form- factors and strong coupling constants. We take the light-cone wavefunctions of the light mesons as basic parameters, and use the light-cone QCD sum rules to study the form-factors of the B meson to scalar, pseudoscalar, vector, axialvector mesons, calculate the one-loop radiative corrections to the twist-2,3 light-cone wave functions terms in a systematic way. Furthermore, we take the B-meson light-cone wavefunctions as basic parameters, and use the B-meson light-cone QCD sum rules to study the form-factors of the B meson to scalar, pseudoscalar, vector, axialvector light (and heavy) mesons, calculate the one-loop radiative corrections to the two- particle B meson light-cone wavefunctions terms in a systematic way. We study the semileptonic and radiative decays of the B meson in details, extract the CKM matrix elements, and search for new physics indirectly.