Quantitative traits of 7 Italian ryegrass varieties were measured in different growth periods and correlation of 30 quantitative traits were analyzed. The results showed that coefficient of variation of the 30 quantitative traits accessions varied from 7.55% to 40.65%, and the variation coefficient of tiller number was the biggest, while the variation coefficient of thousand seed weight was the least. According to the quantitative traits of K-S test and chi-square test, only a small number of properties did not conform to the chi-square distribution; finally, the 28 quantitative traits could be divided into 5 grades, but the time of inflorescence emergence and the tiller number could be divided into 3 grades. The correlation analysis of 30 quantitative traits indicated that the height and the vegetative growth habit, the number of spikelet and the density of spikelet, and the length of upper internode and the number of internode were all showed highly significant negative correlation, while the length of inflorescence and the spikelet density were showed highly significant positive correlation. These results can provide basic information for variety identification, breeding, and quantitative traits classification of Italian ryegrass.