Abstract: Abnormity of Infrared Temperature Field(ITF)approaching instability caused by mutations in the rock itself may focused on a small area.To explore the infrared anomalies precursor in the process of rock rupture instability,we conducted a siltstone infrared monitoring experiment under uniaxial compression.After dividing ITF into three areas including the high temperature zone,the study focuses on analyzing the abnormal characteristic of high temperature zone.The results show that in the process of siltstone rupture instability statistics abnormal precursor of high temperature zone is very obvious,which is characterized by two forms including area ratio,area ratio per Centigrad;and for the abnormal precursor of area ratio and area ratio per Centigrad which all manifests as sharp rise near instability,the frequency of occurrence can respectively reach up to 80% and 60%.In addition,the abnormal precursor emergence of high temperature zone is generally later than peak stress.The results have some value for the infrared monitoring and early warning of rock catastrophe.