For the purpose of satisfying the requirements of fast response to the tasks, a task planning method for area observation with muti-satellites based on imaging resource capability is proposed. Firstly, the formalized description and measure framework of the imaging resource capability, the base of the resource capability calculation, are put forward. Then, the method used to analyze the target observing area coverage with the resource capabilities is studied and the area observing tasks planning algorithm based on imaging resource capability is given. Finally, the above discussions are validated by the testing case.