A study using 3D virtual garment simulation is carried out for the evaluation and application on the pants fit for obese women in their age of 20s and 30s. The results are as follows; 5 obese women in their 20s and 30s were selected for the testing 3D body. They showed no significant differences in all items, comparing with the data of 5th Size Korea body dimensions. The average waist circumstance of the subjects` 3D body dimensions was 87.0cm, hip circumstance was 102.4cm, BMI was 27.1kg/㎡, and their obese body types had similar mean values. Based on the detailed design of ready made pants and the study results of 20∼30s obese women preference for pants design, pants of straight silhouette and semi-tight fit which have waist line lowered, no front dart and one back dart, were manufactured with 100% black cotton and cotton spandex mixed fabrics. When comparing the appearances between real garment and virtual garment, the average of the real garment with 100% cotton was 3.70 and the virtual garment was 4.05. The average of real garment with cotton spandex mixed fabrics was 3.75 and the virtual garment was 4.06. Therefore, the average of virtual garment was highly evaluated. When comparing the results of evaluating the appearance, there was no significant difference caused by materials between real garment and virtual garment. The expression for the ease of virtual garment and real garment was also similar for good evaluation. Thus, 3D virtual garment simulation did positively prove its reliability and effect.