Abstract: Space-based satellite sensors are the important data sources needed to be planned in an emergency mission. Usually, one single space-based satellite sensor cannot fully provide the observation information. According to the dynamic and complex observation needs of emergency task, the program of multiple space-based satellite sensors' observation combination should be generated. In this article, we identify the problem model for a combination of space-based satellite observations based on the needs of a emergency tasks. By setting the weights of the observation requirement factors on-demand, we propose an emergency mission oriented evaluation method for a combination of space-based satellite sensors' observations that can realize a reasonable assessment for selecting the sensors combinations. Experimental results show that the use of this proposed method is a feasible solution for evaluating the program of combinations of observations from different space-based sensors.