  Based on a large group/cluster catalog recently constructed from the DESI
Legacy Imaging Surveys DR9 using an extended halo-based group finder, we
measure and model the group-galaxy weak lensing signals for groups/clusters in
a few redshift bins within redshift range $0.1 \leqslant z<0.6$. Here, the
background shear signals are obtained based on the DECaLS survey shape catalog
derived with the \textsc{Fourier\_Quad} method. We divide the lens samples into
5 equispaced redshift bins and 7 mass bins, which allow us to probe the
redshift and mass dependence of the lensing signals and hence the resulting
halo properties. In addition to these sample selections, we have also checked
the signals around different group centers, e.g., brightest central galaxy
(BCG), luminosity weighted center and number weighted center. We use a lensing
model that includes off-centering to describe the lensing signals we measure
for all mass and redshift bins. The results demonstrate that our model
predictions for the halo masses, bias and concentrations are stable and
self-consistent among different samples for different group centers. Taking
advantage of the very large and complete sample of groups/clusters, as well as
the reliable estimation of their halo masses, we provide measurements of the
cumulative halo mass functions up to redshift $z=0.6$, with a mass precision at
$0.03\sim0.09$ dex.
