Layered double hydroxides (LDHs) are plate-like particles, being potential Pickering emulsifiers. Surfactant modification can regulate their surface properties, and thus can influence their emulsifying behavior. However, there is a lack of full understanding on the correlation between the surface modification of LDHs and their emulsification behavior. In the current work, one LDH and five oleic acid (OA)-modified LDH (LDH@OA) samples were chosen as emulsifiers, and emulsifying tests for pentadecane (oil)-water mixtures were performed at different oil/water volume ratios (1/9−9/1) and solid dosages (Cs, 1.00−10.0 g/L). The type, droplet size, and stability of emulsions were determined. The interfacial adsorption energy (ΔGad) and the coverage of solid particles for droplet surfaces (Rcov) were estimated, and the oil-water interfacial tension and viscoelastic moduli were determined. Results showed that LDH and LDH@OA particles can emulsify the oil-water mixture, forming coalescence-stable Pickering emulsions. The emulsion type is only determined by the solid wettability, independent of the oil/water ratio and Cs. The OA modification can change the wettability of LDH from hydrophilic to hydrophobic, thereby can regulate the type of emulsions from oil-in-water (O/W) to water-in-oil (W/O). Enhancing solid hydrophobicity decreases droplet sizes and increases interfacial viscoelasticity, thus improving the stability of emulsions. The droplet size decreases with an increase in Cs, while it increases with an increase in the volume fraction of dispersed liquid, both independent of the type of emulsions. The solid particles can irreversibly adsorb at the oil-water interface (with |ΔGad|/kT > 107), forming interfacial particle-layers with Rcov ∼0.4 and strong viscoelasticity, which endow the Pickering emulsions with extremely strong stability against coalescence.