The invention discloses a seedling nursery irrigation device capable of effectively saving water resources. The device comprises an irrigation tank, the irrigation tank is internally provided with a waste water treatment tank, a waste water inlet pipe and a sewage discharge pipe, the waste water inlet pipe is connected with a water quality detection tank at the top of the waste water treatment tank, and the bottom of the water quality detection tank is provided with a drainage port A, a drainage port B and a drainage port C; the drainage port A is connected to a water purification device arranged at one side of the bottom of the waste water treatment tank through a drainage pipe A, the drainage port B is communicated with a drainage pipe D arranged at the bottom of the waste water treatment tank through a drainage pipe B, the drainage port C is connected with the sewage discharge pipe through a drainage pipe C, the water purification device is connected with a water outlet pump throughthe drainage pipe D, the water outlet pump is communicated with a main irrigation pipe connected with irrigation branch pipes through a water distributor, and each irrigation branch pipe is providedwith an irrigation sprayer. According to the seedling nursery irrigation device, through the arrangement of the waste water treatment tank, re-utilization of waste water is achieved; the water qualityof the waste water is detected through the water detection tank, the resources are well saved, and meanwhile pollution is avoided.