In view of changes in the water environment in Songnen Plain and water quality problems in recent years, the Second Songhua River Basin was used as our research object. To conduct the water environment investigations, 11 surface water samples and 76 shallow groundwater samples were collected. Multiple methods, such as isotope hydrological analysis, principal component analysis, and irrigation water quality parameter (SSP, SAR, RSC, MAR, KR) analysis were used to systematically apply water chemistry analysis and its evolutionary process, and water quality evaluation for irrigation. The results showed that Ca²⁺ and HCO₃^– were the main ions in the water body. The regional groundwater was recharged by atmospheric precipitation, and the surface water received both atmospheric precipitation and groundwater recharge. The hydrogeological process included the weathering and dissolution of carbonates, and the ion exchange reaction. In addition, the major reaction of local groundwater was the weathering and dissolution of silicate. Water quality was affected by agricultural fertilizer and domestic sewage. The water downstream of the basin, if used for irrigation, might accelerate the formation of alkaline and saline soil, neither