Environmental influence on the signal output of infrared focal plane array (IRFPA) was analyzed. A nonuniformity correction (NUC) algorithm based on environmental and target temperatures was proposed. First, the original signal was captured by UL01011 staring infrared detector. Then, an exponential response model was established according to the principle of least square. Finally, nonuniformity was corrected by this model. Experimental results show that the proposed algorithm can give an exact response in a wider environmental temperature range and enhance effectively the precision of NUC.