1. Objectives The purpose of this study was to objectively diagnose American male and female's production of two vowels /a, i/ by Sasang Constitution. 2. Methods It was analyzed the constitutional characteristics of the American adults voices with PSSC-2004. of 134 cases of vowels /a, i/ with a duration of $2.5{\sim}3$ seconds were inputted in PSSC-2004 and analyzed into 40 factors. 3. Results and Conclusions 1) APQ In the male group's production of vowel /a/, the Soyangin's APQ(l), APQ(3) and APQ(4) were significantly high compared with those of Taeumin and Soeumin. 2) Shimmer In the male group's production of vowel /a/, Soeumin's Octave1 Shimmer was significantly low compared with that of Taeumin and Soeumin. In the male group's production of vowel /i/, Soeumin's D-Shimmer was significantly low compared with that of Taeumin and Soeumin. In the female group's production of vowel /a/, the Soyangin's C-Shimmer was significantly high compared with that of Taeumin and Soeumin. 3) Octave In the male group's production of vowel /a/, the Soyangin's Octave3, Octave4, Octave5, Octave6 and Octave1 Ratio were significantly high compared with those of Taeumin and Soeumin. In the male group's production of vowels /a, i/, the Soyangin's Octave4 was significantly high compared with that of Taeumin and Soeumin. 4) Energy In the male group's production of vowel /a/, the Soyangin's Time Domain Total Sum /Time Domain Count, Freq Domain Total Sum /cnt(0), 0k-4k Total Sum, Dev., A(A#, C, E, D#, E, F#) tot E, and A(C,, D#, F#) Dev. were significantly high compared with those of Taeumin and Soeumin. In the male group's production of vowel /i/, the Soyangin's Time Domain Total Sum /Time Domain Count, Freq Domain Total Sum /cnt(0) and 0k-4k Total Sum, Dev. were significantly high compared with those of Taeumin and Soeumin. 5) Peak In the male group's production of vowels /a/ and /i/,, the Soyangin's Peak1 Ratio was significantly low compared with that of Taeumin and Soeumin. In the male group's production of vowels /a/ and /i/,, the Soyangin's Peak10 Ratio, Time Domain Peak Total/Total Energy Sum, Time Domain Peak Dev. and Total/Total Dev. Sum were significantly high compared with those of Taeumin and Soeumin. 6) It is necessary to expand the research of the acoustic analysis of American and Korean to other countries in the diagnosis of the Sasang Constitution by using the voice characteristics.