The present investigation dealt with observation and experiments concerning the growth and differentiation of hop plant, using the varieties of Cascade(C), Shinshuwase(Sh), and Hallertau(H). The results were as follows: (1) Life cycle of hop plants. The annual growth period of hop plant was devided chiefly into 3 phases, dormant, vegetative and reproductive. (2) Growth of main stem. The hop vine begun to grow in the middle of May and grow vigorousely in the middle and latter of June, then gradually decline or stops at the middle of July and the early of August. (3) Growth of lateral vines. By the statistical analysis, it is judged that the varieties of H and Sh were more grown than that of C. H and Sh were not significant, but H and Sh from C were significant in 5% level. (4) Fresh weight and water content of hop cone. Hop cone in fresh weight of C variety was higher than those of other two varieties and water content of hop cone was decreased with time elapse in three races together. (5) Growing point. Histological view of hop varities in each was different. C showed form of sweet potato, H showed form of round, and Sh showed form of ellipse. (6) Shape of the leaf. C and H were 3 lobes, but Sh is 3∼5 lobes. Generally, the color is dark green. (7) Hop cones. Hop cones are as follows.