Based on the theory of complex adaptive system (CAS), the optimal allocation model of water resources in sewage irrigation areas was established, which provided new ideas and application value for the rational utilization of agricultural production and waste water resources. The results demonstrated that the difference of crop energy capture mainly depended on the development stage. Waste water with a certain concentration was able to promote crop growth, while excessive concentration inhibited crop growth. The correlation between water absorption rate and leaf area index was close (R=0.9498, p<0.01). The amount of bad seeds increased at a speed of 34.7 ? d-1, when system irrigated randomly in the seedling stage, while it tended to remain stable at a speed of 0.3?d-1 after plants entering the mature stage which impacted the total yields of crops.