Abstract: By comparing and analyzing the sensor difference between MODIS and HJ-IRS,we present a newly improved forest fire hotspot detection method which is adaptive to HJ-IRS through improving a new cloud and water mask method and adjusting the threshold value in the MODIS version 4 contextual algorithm.With Heilongjiang area of China and the Far-east area of Russia as the research object,by comparative analysis with the MODIS hotspot products of same area and same time adopting the V4 Algorithm,we find that IRS hotspot product has the same spatial distribution with MODIS,without leak detection.With respect to low temperature small hotspot and its geometric location,HJ-IRS has a preferable performance.