To explore the correlation between the constitutional types in Traditional Chinese Medicine (TCM) and the degree of arteriosclerosis of the people with prehypertension. Methods： We tested 300 patients with prehypertention， hypertention and normotension respectively to figure out their TCM constitutional types and the degree of arteriosclerosis in order to observe how arteriosclerosis degree changes along with different TCM constitutional types. Results： It is found that there was an upward trend in the brachial ankle pulse wave velocity (BaPWV) and the ankle brachial index (ABI). Prehypertention group was higher than the normotension group (P<0.05); there was no difference between prehypertention group and hypertention group (P>0.05). The difference of arterial stiffness among three groups was statistically significant(P=0.000) And there is an upward trend in the degree of arteriosclerosis. Yin deficiency constitution， phlegm dampness constitution and static blood constitution are the risk factors which cause the arteriosclerosis in prehypertensive patients. Conclusion： It indicates an early change of arterial stiffness of prehypertensive patients when BaPWV increases obviously. The degree of arteriosclerosis is related to yin deficiency constitution， phlegm-dampness constitution and static blood constitution.