Objective In view of the difficulty in diagnosis of the closed injury of abdomen and the abdominal bleeding, near-infrared spectroscopy is a non invasive,non-polluting new method for abdominal bleeding detection. Methods Monte Carlo method was adopted to simulate the near-infrared light field distribution model. First of all, we established the abdominal multi-layered biology model. Then, in order to explore the photon absorption between the hydrops abdominis and the blood, a simulation of the light intensity signal between the normal abdomen and the abdominal hemorrhage was made. To determine the location of abdominal bleeding, the article studied the light intensity distribution when the distance between the source and the detector was different. Meanwhile, the article also studied the law of the bleeding volume and the detecting depth to determine the influence of the bleeding on the detection signal and the detecting depth of near-infrared light in the belly. Results In the simulation of seroperitoneum and blood on the absorption of a photon, there was a great difference on the absorption of photons. The simulation results of the bleeding site showed that the detecting depth at the central position of the source and detector line and on the side of the source is the deepest. The detecting depth of abdominal bleeding is 48mm. With a given range, light intensity was in inverse proportion to bleeding volume. Conclusions Near infrared spectrum technology can detect the shallow abdominal bleeding with good sensitivity.