1. Objectives We studied the characteristics of pulse wave variables in hypertensive patients and healthy subjects and would develope the program diagnosing Sasang Constitution. 2. Methods Healthy subjects and hypertensive patients were measured with pulse analyzer. In each of healthy and hypertensive group, means of pulse analyzer variables were compared among Constitution. On these bases of these results, decision tree composed of several rules were developed. 3. Results and Conclusions Decision tree with 72.13% accuracy were developed. (1) if h5(Cheok) < 2.325 & Wm/t(Cheok) < 0.238281 then class = Soeumin (2) if h5(Cheok) < 2.325 & Wm/t(Cheok) ${ge}$ 0.238281 then class = Taeumin (3) if h5(Cheok) ${ge}$ 2.325 & t1(Chon) ${ge}$ 0.143 then class = Soyangin (4) if h5(Cheok) ${ge}$ 2.325 & t1(Chon) < 0.143 & h3/h1(Cheok) ${ge}$ 0.963601 then class = Soyangin (5) if h5(Cheok) ${ge}$ 2.325 & t1(Chon) < 0.143 & h3/h1(Cheok) < 0.963601 & sum of pulse pressure(SPP) of Gwan ${ge}$ 618 then class = Taeumin (6) if h5(Cheok) ${ge}$ 2.325 & t1(Chon) < 0.143 & h3/h1(Cheok) < 0.963601 & sum of pulse pressure(SPP) of Gwan < 618 & t3(Chon) < 0.209 then class = Soeumin (7) if h5(Cheok) ${ge}$ 2.325 & t1(Chon) < 0.143 & h3/h1(Cheok) < 0.936601 & sum of pulse pressure(SPP) of Gwan < 618 & t3(Chon) ${ge}$ then class = Taeumin From above results, we concluded that pulse analyzer is useful instrument to decide Sasang Constitution.