Abstract Ru-based superconductor LaRu2As2 has been discovered exhibiting the highest critical temperature of ~7.8 K among iron-free transition metal pnictides with the ThCr2Si2-type crystal structure. However, microscopic research on this novel superconducting material is still lacking. Here, we utilize scanning tunneling microscopy/spectroscopy to uncover the superconductivity and surface structure of LaRu2As2. Two distinct terminating surfaces are identified on the cleaved crystals, namely the As surface and the La surface. Atomic missing line defects are observed on the La surface. Both surfaces exhibit a superconducting gap of ~1.0 meV. By employing quasiparticle interference techniques, we observe standing wave patterns near the line defects on the La atomic plane. These patterns were attributed to quasiparticle scattering from two electron type parabolic bands.