We present an investigation of the structural and electronic properties of an ordered grain boundary (GB) formed by separated pentagon-heptagon pairs in single-layer graphene/SiO2 using scanning tunneling microscopy/spectroscopy (STM/STS), coupled with density functional theory (DFT) calculations. It is observed that the pentagon-heptagon pairs, i.e., (1,0) dislocations, form a periodic quasi-one-dimensional chain. The (1,0) dislocations are separated by 8 transverse rows of carbon rings, with a period of ∼2.1 nm. The protruded feature of each dislocation shown in the STM images reflects its out-of-plane buckling structure, which is supported by the DFT simulations. The STS spectra recorded along the small-angle GB show obvious differential-conductance peaks, the positions of which qualitatively accord with the van Hove singularities from the DFT calculations.