Galaxies are complex systems including stars, gas, dark matter, and et cetra. The stellar content is best viewed using optical photometry and spectroscopy, while the neutral gas is best traced by the HI 21cm line in the radio band. I will first summarize our previous results on stellar population distribution within galaxies (mostly in 1D radial profiles) made using optical surveys such as Pan-STARRS1 and SDSS-IV MaNGA. I will then introduce our on going and future projects on HI observation towards nearby galaxies using large radio telescopes such as FAST and GBT.