This study aims to explore the effects of bra strap width and elasticity on the comfort of large breast women by three types of widths and elasticities. In the experiment, recruit ten females with C, D, and E cup sizes wore nine experimental bra strap specifications and measured shoulder pressure under bra straps and breast vertical displacement distance at different rates. According to the results, bra strap width and bra strap elasticity have a significant impact on shoulder pressure under bra straps and breast vertical displacement distance. The bra strap width and elasticity combinations have no significant difference in pressure comfort but are related to vertical breast displacement distance. Wider bra straps have better stability than narrower bra straps, and less vertical displacement distance in terms of higher walking speed of 6 km/h.