In the literature “An Autonomous Mission Planning Framework for the New Remote Sensing Satellites”, Mr. Xing separated satellites into 5 modes according to the satellite ability of planning tasks autonomously. NASA and ESA have launched satellites with the ability of mode 5 around about 2000. As for CASC, most of the remote sensing satellites in orbit do not have the ability of mode 4 up to now. In order to satisfy more and more complex user requirements, this article introduces an extensible autonomous task managing strategy, which is taking full consideration of the existing hardware foundation and suitable for multi-loading remote Sensing satellites. In fact, the strategy has been implemented with code, and has been demonstrated in a spacecraft still in development. Adopting this strategy, autonomous task managing ability of the in-orbit satellite can reach mode 4, that is, the satellite can arrange payloads working time by itself according to the tasks, without users considering collisions between each of them.