The invention discloses catalytic characteristics of lesion mimic gene UAP1, and applications thereof. The catalytic characteristics of lesion mimic gene UAP1 are that: OsUAP1 is capable of catalyzing UDPG single-way decomposition, and is not capable of catalyzing UDPG synthesis; OsUAP1 point mutation G280E is capable of reducing enzyme activity; and OsUAP1 is one of the key enzymes of UDPG metabolism. The lesion mimic gene OsUAP1 possesses uridine diphosphate glucose pyrophosphorylase activity, and is capable of catalyzing UDPG decomposition; amino acid point mutation OsUAP1G280E is capable of reducing enzyme activity; OsUAP1 is one of the key enzymes of UDPG metabolism, and UDPG accumulation is a key factor of induction of generation of rice leaf necrotic spots; the application is capable of determining whether OsUAP1 protein possesses uridine diphosphate glucose pyrophosphorylase activity, and the relationship of OsUAP1 protein with plant lesion mimic caused by programmed cell death.