GPS测量在实际生产中已经得到广泛的应用,它也成为一个真正的三维测量工具,它的平面精度是勿容置疑的,但是测高精度仍然没有得到普遍认可。本文讨论了影响GPS测高的几种因素,并以高精度的实时动态差分技术GPSRTK为例论述了GPS测高的可行性及达到的精度指标。-GPS measurements have been widely used in the actual production, it has also become a real three-dimensional measurement tools, plane accuracy is unquestioned, but the measurement precision is still not widely recognized. This article discusses the impact of GPS altimetry several factors, and high-precision real-time dynamic differential technique GPSRTK example discusses the feasibility of GPS altimetry and to achieve the accuracy targets.