A method and a system for providing a roughness haptic sense of a virtual object by using space-time encoding are provided. The method for providing a roughness haptic sense of a virtual object may comprise the steps of: displaying virtual objects to a user; tracking the position of the user's hand; predicting a virtual object, which is most likely to collide with the hand, among the virtual objects; and when the hand touches a haptic sense providing device, controlling the haptic sense providing device on the basis of the surface roughness of the predicted virtual object to feed back a roughness haptic sense to the user.