Full waveform data is one of the core data of GF-7 satellite laser altimeter. In this paper, based on the multi-track measurement data of the GF-7 satellite laser altimeter, the quality of waveform data was evaluated by quality evaluation parameters such as waveform background noise, kurtosis and skewness, signal-to-noise ratio, Gaussian characteristic parameters and other quality evaluation parameters, and the potential of terrain feature extraction from waveform data was analyzed by using Gaussian decomposition of building height calculation and inversion of surface slope. The experimental results show that the overall availability of echo data in the test area is 72.59%, the quality of transmission waveform and echo waveform data is good and stable, and the signal-to-noise ratio is slightly better than ICESat/GLAS. In view of the phenomenon of "flat top" and "undershoot" in waveform data, a preliminary processing method is given, and the selection of waveform data is optimized by combining high and low gain. The waveform data can well reflect the terrain characteristics of ground objects, and the echo waveforms of different ground objects present corresponding waveform characteristics. The accuracy of buildings height deduced from waveform data can reach decimeter level.The related conclusions have reference value for the application of laser altimeter data of GF-7 satellite.