A method for simulating, by means of a computer, an image of a twisted yarn (1, 2)in which twisting of a plurality of yarns is simulated and an image of a twisted yarn is formed, the method comprising: an image input step of, by the computer, inputting two-dimensional scanned or photographic images of the plurality of yarns used for twisting, the respective yarns being linearly extended; an abstracting step of, by the computer, producing, for each of the images that have been input in the image input step, a three dimensional abstracted model (3, 4) of each of the yarns that extends in one direction and has a certain cross-section of a rounded shape to abstract each of the yarns, and of setting correspondence between each of the abstracted models and the images; a twisting step of, by the computer, twisting, according to a predetermined condition, the abstracted models of the plurality of yarns that have been abstracted in the abstracting step and of producing a three dimensional abstracted model of a twisted yarn in a form extending along a central axis thereof; a projection step of, by the computer, projecting the abstracted model of the twisted yarn that has been produced in the twisting step onto a plane that is in parallel with the central axis to form two-dimensional corresponding projected images of the abstracted models of the yarns thereon; and an image reproduction step of, by the computer, reproducing, based on the correspondence that has been set in the abstracting step, the images of the yarns on the corresponding projected images of the abstracted models of the yarns included in the abstracted model of the twisted yarn that has been projected onto the plane in the projection step. an image input step of, by the computer, inputting two-dimensional scanned or photographic images of the plurality of yarns used for twisting, the respective yarns being linearly extended; an abstracting step of, by the computer, producing, for each of the images that have been input in the image input step, a three dimensional abstracted model (3, 4) of each of the yarns that extends in one direction and has a certain cross-section of a rounded shape to abstract each of the yarns, and of setting correspondence between each of the abstracted models and the images; a twisting step of, by the computer, twisting, according to a predetermined condition, the abstracted models of the plurality of yarns that have been abstracted in the abstracting step and of producing a three dimensional abstracted model of a twisted yarn in a form extending along a central axis thereof; a projection step of, by the computer, projecting the abstracted model of the twisted yarn that has been produced in the twisting step onto a plane that is in parallel with the central axis to form two-dimensional corresponding projected images of the abstracted models of the yarns thereon; and an image reproduction step of, by the computer, reproducing, based on the correspondence that has been set in the abstracting step, the images of the yarns on the corresponding projected images of the abstracted models of the yarns included in the abstracted model of the twisted yarn that has been projected onto the plane in the projection step.