Sward measurememt using the tiller marker technique was carried out to study the dynamics of the grazing process by dairy cows in the Lolium perenne sward during five days of continuous paddock grazing through three experimental periods. Herbage mass progressively decreased with the progress of grazing down. Biomass and density of live leaves reduced with a more sensitive pattern than those of dead material and leaf sheath as grazing advanced. The average density of live decreased from 530 to 85 ㎏OM/㏊/cm. All live leave, vertically distributed to 2S ㎝ were defoliated after live days of grazing. Depth of grazing and daily proportion of defoliated tiller decreased exponentially as Grazing proceeded down. The bite depth averaged 35.8 % (±2.16 %) of the height of defoliated tillers before gracing with a range of 349 to 147 ㎜ through the three experimental periods. The maximum and minimum depth of grazing were reduced from 121 and 94 ㎜ on the last day to 75 and 63 ㎜ on the last day of grazing. The average grazed area decreased also from 1018 to 62.8 ㎡. The significant(p$lt;0.05) correlations between extended tiller height and the proportion of defoliated tiller(r=0.86), grazing depth(r=0.97), or grazed area(r=0.52) were obtained. These results suggest that the measurements of current sward height and sward structure appear to be a very useful means of studying the daily dynamics of herbage utilization.