We are entering a golden age of high-precision cosmology, driven by new-generation large-scale sky surveys (including China's CSST). Galaxy clusters, the universe's largest structures, can be used as powerful "cosmic probes" to illuminate the dominant yet invisible components of the universe: dark matter and dark energy. In this talk, I will present some of our past attempts to find and characterize the galaxy groups/clusters from both large spectroscopic and photometric redshift surveys and their applications in the galaxy formation and cosmological studies. I will also spend some time describing the recent progress of JUST, and its role in the future cluster cosmological probes.
