The utility model discloses a rotating step ladder device and an engineering machinery vehicle. The rotating step ladder device comprises a fixed seat and a step ladder main body. The fixed seat further comprises a vehicle bonding part, a rotating positioning part, a first positioning part and a second positioning part, wherein the vehicle bonding part is fixedly connected with a main body of a vehicle. The step ladder main body further comprises a step ladder rotating part and a status positioning part, wherein the step ladder rotating part is rotatablely fixed on the rotating positioning part through a first hinge pin and the status positioning part is connected with the first positioning part or the second positioning part through a second hinge pin to correspondingly achieve spreading out positioning status or retracing positioning status of the step ladder main body. The rotating step ladder device and the engineering machinery vehicle has the advantages that the rotating step ladder device and the engineering machinery vehicle can optimize vehicle body structure, facilitate running of vehicles, prevent vehicles from linking and colliding with other irrelevant objects in the process of running, and improve cross-country power of vehicles.