Objective To measure the thicknesses of proximal limb muscles in healthy adults which provides a basis for clinical diagnosis and analyze their possible influencing factors.Methods 88 healthy volunteers （18~70 years old） were enrolled， and genders， ages， body mass indexes (BMI) values and exercise habits were recorded. Thicknesses of the triangle， biceps brachialis， rectus femoris and lateral femoral muscle were measured by ultrasound.Results Thickness of the triangle， biceps brachialis and lateral femoral muscle had no significant difference between the left and right sides. The muscle thicknesses of males were thicker than those of females， and the differences were statistically significant (P<0.05). The thicknesses of rectus femoris and lateral femoris in the 18~45 age group were thicker than those in the 46~70 age group. There were negative correlations between rectus femoris or lateral femoris and ages (r=-0.293， -0.357， P<0.05， respectively). The differences of muscle thicknesses among different BMI values were statistically significant (P<0.05). The higher of the BMI values， the thicker of the muscle thicknesses. The muscle thicknesses were positively correlated with BMI values， and the r value were 0.320~0.505(P<0.05).Conclusion There was no significant difference in the muscle thicknesses detected by ultrasound between the left and right sides. But different muscles showed different thicknesses. The proximal limb muscle thicknesses were affected by gender， ages， BMI values and motion states， and different muscles had different influence factors. The above provided a reference basis for the evaluation of muscle thickness changes in idiopathic inflammatory myopathies which often involve the proximal muscles of the extremities.