  Based on the disk galaxy formation theory within the framework of standard
LCDM hierarchical picture, we selected modelled DLAs, according to their
observational criterion, by Monte Carlo simulation with the random inclinations
being considered, to examine their observed properties. By best-fitting the
predicted metallicity distribution to the observed ones, we get the effective
yield for DLAs about 0.25Z_sun, which is comparable to those for SMC and LMC.
And the predicted distribution is the same as that of observation at the
significant level higher than 60%. The predicted column density distribution of
modelled DLAs is compared with the observed ones with the corresponding number
density, gas content being discussed. We found that the predicted number
density n(z) at redshift 3 agree well with the observed value, but the gas
content \Omega_DLA is about 3 times larger than observed since our model
predicts more DLA systems with higher column density. It should be noted that
the predicted star formation rate density contributed by DLAs is consistent
with the most recent observations if the star formation timescale in DLAs is
assumed to be 1 to 3 Gyr. Meanwhile, the connection between DLAs and LBGs is
discussed by comparing their UV luminosity functions which shows that the DLAs
host galaxies are much fainter than LBGs. We also predict that only few percent
of DLAs can host LBGs which is also consistent with current observations.
However, there is a discrepancy between model prediction and observation in the
correlation between metallicity and HI column density for DLAs. We suggest that
this could result from either the inadequacy of Schmidt-type star formation law
at high redshift, the diversities of DLA populations, or the model limitations.
