Thanks to the dramatic development of astroparticle experiments over the last few decades, new insights into the sources have been provided. Which takes multi-messenger astronomy aiming at combining information from different messenger particle to a new era.In this talk, I will discuss two interesting astro objects, Fermi bubbles and Centaurus A, based on their multi-messenger observation. The Fermi bubbles (FBs) are two giant gamma-ray lobes above and below the Galactic center. In their hadronic scenario, the acceleration of protons and/or nuclei and their subsequent interactions with gas in the bubble volume can produce the observed gamma rays and high-energyneutrinos as counterparts. I will talk about the derived models with the latest HAWC, IceCube and Fermi detection and will present a sensitivity study of Cherenkov Telescope Array (CTA) to our FB hadronic model with the morphological analysis and classical on/off analysis based on the realistic CTA deep central and extended survey. Motivated by the observed excess UHECR signal above 55 EeV by Auger, the HESS GeVTeV gamma rays detection and the 8-year Fermi-LAT data fromCentaurus A (Cen A), we try to understand the origin of its spectral hardening with two emitting zones in the jet of Cen A. We consider two scenarios: (i) Two zone synchrotron self-Compton (SSC) and externalCompton (EC) models, (ii) Two zone SSC, EC and photo-hadronic emission from cosmic ray interactions. Photo-hadronic emission in scenario (ii) can explain VHE data with the same spectral slope as obtained through fitting UHECRs from Cen A.