For the mathematical model of conventional three-dimensional two-phase non-distributive and distributive tracer problems, there are unknown parameters Cww (the concentration of water component in water phase)and Coo (the concentration of oil component in oil phase) in the water and oil component functions, which would increase the amount of calculations in the basic model to solve difference. Taking into account Cww≈1 and Coo≈1, the water and the oil component functions can be simplified through substituting Cww=1 and Coo=1. The implicit difference schemes of this simplified model are presented and solved by Gauss-Seidel iteration method. By means of rational design of the differential lattice, the obtained coefficient matrix of linear equations is strictly diagonally dominant, which can make the result unconditionally stable. Compared with the results of the non simplified model, the formation permeability error is less than 2%, and the layer thickness error is less than 5%, which indicates the operation accuracy of this simplified model can meet the requirements, and greatly reduce the calculated amount at the same time. The model has been put into practical use for the well group N2-2-P38 in southern district Ⅱin Daqing Oilfield. The amount of 10 tons ammonium thiocyanate was injected into the test area, and the amount of 14 tons normal butyl alcohol was used. The production concentration curves have been measured in three nearby production wells, and one of them is not perforation and the tracer is not detected. The time at which ammonium thiocyanate concentration achieves peak value is 152, 225and 42 days. The flowing velocity of injected water between the injection and the production wells is 1.65, 1.11 and 5.95 m/d. Then the average water-phase permeability of the reservoir is 0.090, 0.0731 and 0.477μm², which are calculated and determined for production wells N2-D3-P38, N2-D2-P38 and N2-2-P138, respectively. Based on the dynamic parameters of water cut, production fluid, pressure and the curve fitting of tracer concentration, the reservoir parameters and remaining oil saturation distribution of the 4 sediments, namely, PI1, PI2, PI3 and PI4 are obtained.