Soil is the basis of plant growing development.The total nitrogen content in the soil is a key factor determining the plant nutrient levels.Soil moisture is also one of the most important parts of the soil.It is not only a necessary condition for plant growth, also has an important significance on the heat balance, soil temperature and moisture of agriculture.It is important to master the distribution status of soil nutrient in real-time.Traditional measurement methods are costly, labor intensive, and time consuming.Near infrared spectroscopy (NIRS) is a powerful tool in the analysis of the soil compositions as well as soil physical and chemical properties.Therefore,near infrared spectroscopy analysis method becomes a feasible method to detect TN/moisture content non-destructively.This research aims at developing a two-parameter detector which can measure TN and moisture content in soil simultaneously.In this research, 270 soil samples were collected from the farmland in Shangzhuang experimental station of China Agricultural University located in the suburb of Beijing.Soil samples were collected from different experimental areas and depth at same level.The near infrared spectral reflectance of each sample was measured by using a MATRIX-Ⅰ analyzer.The sensitive wavebands (1375nm, 1520 nm, 1861 nm, 2100 nm, 2286 nm,2387 nm are sensitive to TN and 1450 nm and 1920 nm are to soil moisture content) were determined after analyzing the spectra characteristics of soil samples with different parameter concentrations (TN and moisture).The detector was developed using eight determined wavebands.It consisted of optical unit and control unit.The optical unit included eight light sources, an octagonal umbrella-shape structure and one photoelectric sensor.The control unit comprised of an amplifier circuit, a filter circuit and a JN5139 module which was responsible for A/D conversion,data transmission, display, calculation and data storage.The optical system is designed as an octagonal umbrella which centered on the photoelectric detector.And the near infrared laser light sources of eight wavelengths are uniform distributed on the eight sides of the structure in order to insure the emitted light from the sources could shoot into the soil surface in the same angle and reflect to the photoelectric detector.Subsequently, the collected electrical signal was processed and the reflectance was obtained separately for each optical channel.Then TN and moisture content are calculated using their corresponding forecasting models.Finally, eight reflectance and two detected results are transmitted to the receiver of PDA and displayed.After the laboratory test, it could be concluded that the in-situ soil two-parameter detector work well comparing with the standard spectrometer instrument.It could detect soil samples reflectance at the specific waveband efficiently, which provides an important base on developing a portable soil reflectance parameter detector.And in the in-situ experiment, the R2 reaches 0.6132, the RMSEC is 0.1896 mg/Kg.The results show that the detector achieves a practical level in predicting the TN and moisture content of soil samples.It can be concluded that the detector shows the practical significance for two soil parameters detection in real time.In the next step, long-term use should be launched in farmland.