The invention discloses a method for automatically adjusting the posture of a Ka wave-band mobile satellite communication antenna and a device, wherein, three axes-an azimuth axis, a wobble shaft, and a pitch axis which drive the antenna to rotate are firstly arranged on a pedestal of the antenna in a space orthogonal mode to realize angular motion isolation of the three space orthogonal axes; then an antenna component is respectively configured with the azimuth axis, the wobble shaft, and the pitch axis as a center to lead an overall centroid of the antenna component installed on the pitch axis to fall on the pitch axis, the overall centroid of the antenna component installed on two sides of the axes of the wobble axis to fall on the wobble axis, and the overall centroid of the antenna component on the azimuth axis to fall on the azimuth axis; finally based on the antenna as a detecting standard of the antenna pointing deviation, pointing deviation caused by drifting of a sensor is eliminated by tracking a beckon signal of a satellite and alternately driving an intersection angle of the azimuth axis and/or the pitch axis, thus ensuring the antenna in an optimal receiving state. The method for automatically adjusting the posture of Ka wave-band mobile satellite communication antenna and the device have the advantages of high precision, simple structure, small volume, and low cost, can be widely applied to emergency communication, rescue and relief work, and also can be used for commercial purpose in vehicles, ships, trains, and the like.