  With a consistent definition of transverse-momentum-dependent(TMD) light-cone
wave function of $B$-meson, we show that the amplitude of the radiative
leptonic B-decay can be factorized at one-loop level as a convolution with the
wave function and a perturbative coefficient function, combined with a soft
factor. In this TMD factorization, the transverse momenta of partons in the
$B$-meson are taken into account and all soft divergences are contained in the
wave function and the soft factor. The coefficient function is infrared-safe.
The factorization works on a diagram-by-diagram basis and is possible to extend
beyond one loop. With the factorization the large logarithms in the
perturbative function can be simply resummed. Our work shows that the result of
collinear factorization for the decay can be derived from that of TMD
factorization. Therefore, the two factorizations for the case here are simply
related to each other.
