For inhomogeneous lattices we generalize the classical Gaussian model, i.e.
it is proposed that the Gaussian type distribution constant and the extern
al magnetic field of site i in this model depend on the coordination number
q(i) of site i, and that the relation b(qi)/b(qi) = q(i)/q(i) holds among
b(q)'s, where b(q) is the Gaussian type distribution constant of site i. Us
ing the decimation real-space renormalization group following the spin-resc
aling method, the critical points and critical exponents of the Gaussian mo
del are calculated on some Koch type curves and a family of the diamond-typ
e hierarchical (or DH) lattices. At the critical points, it is found that t
he nearest-neighbor interaction and the magnetic field of site i can be exp
ressed in the form K-* = b(q)/q(i) and h(qi)(*) = 0, respectively. It is al
so found that most critical exponents depend on the fractal dimensionality
of a fractal system. For the family of the DH lattices, the results are ide
ntical with the exact results on translation symmetric lattices, and if the
fractal dimensionality d(f)=4, the Gaussian model and the mean field theor
ies give the same results.