Quantum spin Hall effect, usually existing in two-dimensional (2D) topological insulators, has topologically protected helical edge states. In the year 2014, there was raised a theoretical prediction that monolayer transition metal dichalcogenides (TMDs) with 1 T'phase are expected to be a new class of 2D quantum spin Hall insulators. The monolayer 1 T'-WTe ₂has attracted much attention, because it has various excellent characteristics such as stable atomic structures, an obvious bandgap opening in the bulk of monolayer 1 T'-WTe ₂, and tunable topological properties, which paves the way for realizing a new generation of spintronic devices. In this review, we mainly summarize the recent experimental progress of the 2D quantum spin Hall insulators in monolayer 1 T'-WTe ₂, including the sample preparation via a molecular beam epitaxy technique, the detection of helical edge states and their response on external magnetic fields, as well as the modulation of more rich and novel quantum states under electron doping or strain. Finally, we also prospect the future applications based on monolayer 1 T'-WTe ₂.