Abstract: The research resuits show that when water Level in artesian wells shows step-variations, the discharge shows synchronous wariationa.Based on this, a mathematic model has deen estalished:ΔV=Δh.Su + ΔQ.τ, that is, the encreased quantity of water quantity flowed to the well from aquifer is equal to the sum of the volume accupied by water level step-variation quantity and the water volume discharged from water pipe by variational quantity of discharge within a certain time。According to the relationship between water level and discharge in artesian wells, that is, Q=C(2gh)^1/2, and water level and discharge data in wanquan well,and by formula computation, it has been proved that the anomalous amplitude of water level step-variations in Wanquan well is directly proportional to the water level observation value.