  Sfermion masses and eigenstates in the supersymmetric economical 3-3-1 model
are studied. By lepton number conservation, the exotic squarks and
superpartners of ordinary quarks are decoupled. Due to the fact that in the
3-3-1 models, one generation of quarks behaves differently from other two, by
R-parity conservation, the mass mixing matrix of the squarks in this model are
smaller than that in the Minimal Supersymmetric Standard Model (MSSM). Assuming
substantial mixing in pairs of highest flavours, we are able to get mass
spectrum and eigenstates of all the sfermions. In the effective approximation,
the slepton mass splittings in the first two generations, are consistent with
those in the MSSM, namely: $ m^2_{\tilde{l}_L} - m^2_{\tilde{\nu}_{l L}} =
m_W^2 \cos 2\ga$ $(l=e, \mu)$. In addition, within the above effective limit,
there exists degeneracy among sneutrinos in each multiplet:
$m^2_{\tilde{\nu}_{l L}} = m^2_{\tilde{\nu}_{l R}}$. In contradiction to the
MSSM, the squark mass splittings are different for each generation and not to
be $ m_W^2 \cos 2\ga$.
