Application of chitosan oligosaccharide and composition thereof in resisting intense light for crops

The invention relates to an application of chitosan oligosaccharide and composition thereof in resisting intense light stress for crops, and particularly provides a farm chemical composition for crops to resist intense light. The farm chemical composition comprises the chitosan oligosaccharide, and the weight percentage of the chitosan oligosaccharide in farm chemical composition is 0.01 to 0.02 percent or 0.005 to 0.015 percent. The chitosan oligosaccharide composition is applied before crops suffer from the stress of intense light or after the crops suffer from the stress of the intense light, so not only can the crops be prevented from being damaged by the intense light, but also the damage of the intense light on the crops can be reduced.