This study aimed to investigate the most effective exercise in relation to the effect on the cross-sectional area (CSA) and muscle tone of the abductor hallucis in patients with hallux valgus. Thirty-six patients (18 men, 18 women )with a mean age of 22.14 years (standard deviation of 2.47 years) participated voluntarily in this study. Hallux valgus was defined as an angle >15° of the 1st metatarsophalangeal joint(MPJ). A goniometer was used to determine the angle of the 1st MPJ. In addition, an ultrasound system and Myotone Pro were used to collect the CSA and muscle tone of the abductor hallucis of the dominant foot. CSA and muscle tone of the abductor hallucis were measured in four positions: resting position, during short foot (SF) exercise, during toe-spread-out (TSO) exercise, and during towel-curl(TC) exercise. For all data, one-way repeated analysis of variance test was used to compare the dependent variables according to the three exercise methods, and a post-hoc test was performed using the Bonferroni modification method. The significance level was set to p < .05. The CSA and muscle tone of the abductor hallucis were significantly increased in the TSO and SF exercises. In addition, a more significant increase was found in the TSO than in the SF exercise. However, no significant difference was found in TC. In conclusion, the TSO exercise is the most effective for selectively contracting the abductor hallucis than other exercises.