In order to study the effect on scenery radiation energy acquisition and signal-to-noise ratio of short-wave infrared (1.0-2.5 μm) imaging spectrometer caused by prism nonlinear dispersion,the expressions of radiation energy collection and spectrum sampling calculation are deduced,which are calculated and analyzed in the range of short-wave infrared spectrum. It is indicated that when the number of spectral channels is same,compared to equal interval spectral sampling method,the scenery radiation energy collected by a single prism dispersive imaging spectrometer detector is relatively higher in the 1.0-1.85 μm range,but it is relatively lower in the 1.85-2.5 μm range,and the signal-to-noise ratio has similar characteristics. The weak absorption feature of atmosphere is more and more clearly apparent,when the number of spectral sampling channels increases.