For the satellite to ground data transmission in the space-based satellite network, the worst channel conditions shall be considered, that is, the link budget shall be carried out according to the lowest elevation angle and the farthest transmission distance. It is extremely urgent to make full use of the limited link power resources. An efficient adaptive data transmission method is proposed to make the satellite data transmission rate increase with the increase of elevation angle, so as to maximize the amount of data transmitted from the satellite transit window, the reliability and throughput of information transmission are improved. And the effectiveness of this method is verified by computer simulation.