The contamination of livestock and poultry breeding is one of the major factors that introduce the rural non-point source pollutions. The scientific and proper use of livestock and bird cultivation wastewater for field irrigation after rational handling, already has become the effective approach in saving water and fertilizer and protecting the rural area water environment. But the research is just beginning, and restricted to short-term experimental study, and research on simulation of contaminant transportation and transformation for long-term field irrigation has not been reported. For this purpose, utilizing the piggery wastewater irrigation field experiments in Yangliuqing of Tianjin, the following things were achieved: building the coupling model of winter wheat with soil water-heat-nitrogen transport, proceeding calibration and validation of the model parameters, based on the HYDRUS-1D model and importing the CLIMGEN model, statistical analysis of the actual irrigated area of 30 years meteorological data to generate the daily weather data of 50 years in the future, and coupling simulation models built for integration. The coupling model was used to study stochastic simulation and statistical analysis of nitrogen transport-transformation and nitrogen leaching under stochastic precipitation and variable climatic conditions, different irrigation water quantities and water qualities under long-term breeding wastewater field irrigation, and it was found that the anaerobic water under medium irrigation amount is the optimal irrigation pattern taking water leakage, nitrogen leaching and other factors into account. The results provided the reference for the utilization of livestock and poultry breeding wastewater as resources.