This study aimed to develop a basic bodice suitable for the body shape of women in their 50s by using the CLO 3D virtual clothing program to create an avatar with the standard body presented in KATS (2022). A pattern was designed and produced using the CLO program, and the virtual fitting was evaluated. First, it was possible to confirm the slope (profile line) from the front center line to the point in front of the neck, the sagging shape of the breast, and the change in body shape due to the increase in bust circumference using the CLO program. Second, the change in body surface and body surface length according to movement was used to identify the profile line. The bust dart was very large. and the bust circumference showed the largest changes (5.05% in the 90° side and 1.5% of the breast width). Third, the total length reference line of the basic bodice was the back length (actual measurement). The total width reference line was the bust circumference/4+2cm and the breast width+0.5cm. The armhole depth reference line was the bust circumference/4–2. A profile line was created from the front neck circumference to the neck shoulder point to the breast point. Darts were formed on the back shoulder and back armhole lines. The allowances were 8 and 6cm for the bust and waist circumferences, respectively. All virtual fitting evaluation items improved significantly over two rounds (from 3.69/5 to 4.66/5 points).