In the matrix model approach to M/string theory, a general prescription of
the large N limit is still elusive. To gain insights into the scaling limit
, Re study the quantum fluctuations around a given diagonal background of t
he large N matrix model in the weakly coupled regime. The perturbative expa
nsion in matrix theory is explicitly shown to be identical to the Feynman a
mplitudes of gauge theory, provided that the D instanton configuration spac
e is interpreted as (discretized) loop momentum space. This enables us to s
tudy how the structure of large N divergence is related to the ordinary UV/
IR divergences in QFT. Various bounds on the scaling exponents are also dis
cussed.