Irrigation with untreated wastewater, especially the wastewater containing several toxic substances, would cause serious farmland pollutions in some irrigation zones and reductions on the quality and yield of agricultural products. Moreover, some heavy metals and toxic substances in wastewater would enter the human food chain through agricultural products, and some excessive nitrogen would pollute the groundwater or flow into the surface water, resulting in excessive nitrites in drinking water. All of those will affect human health severely. Generally, a large amount of salts exist in wastewater, and therefore irrigation with them would bring about damages on soil structure or induction of soil salinization. Consequently, studies on the improvement of pretreatment technologies on wastewater and promotion of irrigations with reclaimed water are of great significance on both the protection of eco-environment and the promotion of economic benefits. Besides, strengthened management and regular monitoring are required for utilizing the reclaimed water resource scientifically and reasonably.