In this work, hydrogen embrittlement behavior of nickel-based superalloy (Inconel718) was investigated under different hydrogen charging times and then mechanically characterized with the slow strain rate tensile test. Specimens were first cathodically charged for 40, 80 and 120 hours (h). Surface cracks and fractography within gauge part were examined and characterized subsequently by using high-resolution Scanning Electron Microscope (SEM) after tensile test. It was observed that slip bands and cracks appeared on the surface after cathodic charging. A transition from brittle to ductile fracture mode was seen on the fracture surface after loading to failure. Both intergranular and transgranular fracture modes were observed. The increase in yield strength of electrochemically charged samples indicates the interaction between hydrogen and dislocation which links to hydrogen-enhanced localized plasticity (HELP) mechanism.