To explore the characteristics of hexoploid triticale (×Triticosecale Wittmack) for forage and understand their basic development rule, two types’ six hexaploid triticale genotypes were used to investigate their plant heights, lengths of inter-nodes, plant height components and dynamic changes of plant height, and the reaction of triticale plant height to GA3 were studied in 5 concentrations and at 2 development stages. The results showed that the plant heights of triticale varieties for forage were significant higher than triticale genotypes for food or feed. And the difference of height is mainly due to the length of upper inter-nodes. The plant height was significantly positive correlation with plant height component factors, length of inter-nodes L1 and L2 contributes more to triticale plant-height. No significant difference of plant height components indexes were found between the two types of triticale. The dynamic changes of triticale height indicated that the max development speed of forage triticale about 10 days later than the dual types. GA3 enhanced the plant height development more for forage triticale and the sensitivity was more at heading stages than at shooting stage. These results will supply some theory bases for forage triticale cultivation.