There is provided a rotatable and hung safety window assembly comprising: a housing having opposite holes defined in opposite inner side walls thereof respectively; a guide chassis disposed in an upper space in the housing, wherein the guide chassis has opposite guide grooved lines defined in opposite inner side walls thereof respectively; a rotatable chassis disposed in a lower space in the housing, wherein the rotatable chassis has opposite hinge protrusions formed on opposite outer side walls thereof to correspond to the opposite holes respectively, wherein the hinge protrusions are hingedly received in the holes respectively; an upper window having opposite guide protrusions formed on opposite outer side walls thereof, wherein the guide protrusions are slidably received in the first guide grooved lines; and a lower window fitted into the rotatable chassis.