To reduce the cost of near-infrared endoscopic image equipment and the reconstruction time, a measurement method based on the effective detection area is proposed and the corresponding algorithm which simultaneously reconstructs the absorption coefficient and the reduced scattering coefficient is developed. Firstly, the effective detection area corresponding to an irradiation point is investigated with the Monte Carlo simulation. Secondly, the image reconstruction algorithm based on the effective detection area is studied. Finally, the impact of the number of measured points in the effective detection area on the reconstructed results is discussed, and the developed algorithm is verified by the simulation data. The results show that the reconstructed algorithm based on the effective detection area has equivalent accuracy to the traditional ones. The fidelities of the reconstructed absorption and reduced scattering coefficient can be up to 60% and 80%, respectively. The scales and positions of the reconstruced lesions are both corresponding to the true values and the reconstruction time is reduced by a half. The detection using the effective detection area and the developed reconstruction algorithm will promote the development of diffuse optical tomography which is applied to cervical and other tubular organs.