With the progress of the research of navigation system, navigation system has been widely applied in many areas such as highaltitude reconnaissance. Meanwhile, the application environment of navigation system may change, such as the change of indoor and outdoor environments. However, research at home and abroad are more inclined to single environment, and the algorithms are applicable only to a single environment. There are relatively fewer studies about panoramic environment algorithms. An four rotorcraft attitude estimation algorithm is presented. The algorithm can take different attitude calculation model according to the environment and the motion state of the four rotorcraft, and switch mode by the comparison between the variable and the threshold value. Experiments indicated that the algorithm can realize seamless switch when the environment of the four rotorcraft changes, has high accuracy, and has a good real time capability.