Semiconductor/electrolyte interface is at the heart of our understanding of electrocatalysis, photocatalysis and electrophotocatalysis. Both the nature of interfacial reaction and the structure of electric triple layers(ETL) dictate the chemistry and the physics of electrified interfaces. In one hand, the interfacial reaction comprises proton and electron transfer reaction. Assisted by deep neural network (DNN), the free energy curve for proton transfer can be well obtained from molecular dynamics simulation in the time scale of nanosecond.The redox potential for electron transfer reaction is computed by referring to the standard hydrogen electrode (SHE). For proton coupled electron transfer (PCET), we develop a theoretical method for computing kinetic rate constant, which adopts the Stuchebrukhov-Hammes-Schiffer kinetic theory. On the other hand, the differential capacitance is the key property for characterizing ETLs. Hence, we develop a theoretical model for computing the differential Helmholtz capacitance of oxide−electrolyte interfaces using density functional theory-based finite-field molecular dynamics simulations.