A total of 71 wheat straw samples of different varieties were collected from different locations of China. 54 samples were selected as calibration set, and the rest 17 samples were taken as validation set. Static and simulated online quantitative analysis models of net calorific value of wheat straw were established in laboratory by two different near-infrared spectrometers—Spectrum 400 and Antaris Target, respectively. Spectrum 400 was used for rapid detection in a static mode. The determination coefficient and the relative analysis error of calibration set were 0.90 and 2.75. Antaris Target was used to simulate on-line detection. The determination coefficient and the relative analysis error of calibration set were 0.93 and 3.26. Moreover, the static and simulated online models were compared and discussed.