This paper describes the working principle and main technical indices of the newly developed CD 10 field portable gamma ray full spectrometer.Its gamma ray energy analytical range is 30～3 000 keV,it has 1 024 analytical channels,its ¹³⁷Cs energy resolution ratio is lower than 12%,and the digital spectrum stabilizing technique is adopted instead of radioactive spectrum stabilizing reference source so as to realize noninterference natural gamma ray full spectrometry.With the examples of its application to geological evaluation in nuclear environment,the paper illustrates main characteristics and prospects of the gamma ray full spectrometer.