Abstract: Innovative design on flattening system of grass cutting flattening machine was carried out based on TRIZ theory.The reason of low flattening rate for flattening system was analyzed.4 kinds of innovative design solutions were put forward using material field analysis method，contradiction matrix method and cause and effect analysis method.The optimal scheme was established through comparative analysis.New conditioner roll was designed innovatively.Flattening rate test of 2 prototypes was made.Results showed that flattening rate of conditioner roll increased from 85% to 96% after improved design.It reached the standard set of indicators and could be meet harvesting requirements of high quality forage.