Abstract: In this paper，fire detection threshold of the first half year in Sichuan province were studied．The data we used above MOIDSL1B data from January to June，2009～2012 and we refers the ground observation data for forest fire come from Forest Fire Prevention Office in Sichuan province．Acquired the MODISL1B data except cloud and water，and used it to back calculate the brightness temperature．Finally，get the fire detection threshold in the first half year according to different fire type，in addition，modified the monitoring algorithm appropriately．Using the modified algorithm for the monitoring of fire in February 2012，and the accuracy reached 87%，monitoring results are better than MODIS14 fire products．In order to further verify the reliability of the results，the research overlaid the resultant fire point，wind field and the land use data，and used the MODIS of 7，2，1 band combination to strengthen the accuracy of fire point location．