HII regions are an excellent tracer of high-mass star-forming regions and current star formation in galaxies. In particular, young O/B stars produce powerful outflows and intense UV radiation that appreciably change the chemistry and physical conditions in the surrounding HII regions. First, I will present large surveys studies of the (sub)millimeter hydrogen radio recombination lines (RRLs) and molecular lines toward 967 compact dust clumps (409 clumps for molecular lines) identified in the APEX Telescope Large Area Survey of the Galaxy (ATLASGAL). The atomic/molecular lines surveys, taken from the IRAM 30m, Mopra 22m, and APEX 12m telescopes, show the HII regions are obviously associated with the dense clumps and some of them show evidence of high-velocity ionized gas. By determining column densities and abundances of the selected eight molecular transitions (HCO, HOC+, C2H, c-C3H2, CN, H13CN, HC15N, HN13C), HCO and C2H known as photodissociation tracers show excellent correlations with the presence of the young HII regions and their abundances decrease with an increase of H2 column densities. In the second part, I will show recent 1.3 mm ALMA data analyses of three ATLASGAL HII regions. The ALMA data with high angular resolutions (0.7-0.8’’) has resolved detailed molecular gas structures surrounding the HII regions with cometary morphology and hidden hot cores in the regions.