The invention discloses a pipeline cutting machine for a water conservancy project. The pipeline cutting machine structurally comprises a motor, a fixing device, a fixator and a control switch, wherein the fixing device is provided with a supporting mechanism, a rotating mechanism, a supporting rod and a fixing base, and two supporting blocks are distributed on the lower surface of a circular pipeline in a left-right mode, so that when an arc-shaped plate is compressed by the circular pipeline, a gap is generated between the supporting blocks, the effect of uneven stress points of the arc-shaped plate is achieved, the stress points of the circular pipeline are prevented from being too even, the circular pipeline is prevented from sliding, a rubber block drives a rotating block to compressa spring downwards, the effect of allowing the circular pipeline to pass through is achieved, a sliding ball slides on the inner side of a clamping ring by manually rotating a rotating rod, then a rotating ring can rotate reversely, the circular pipeline can be disengaged, the sliding ball is clamped to the inner side of the clamping ring when rotation is stopped, the rotating mechanism is distributed at the upper end of the supporting mechanism, the circular pipeline is fixed through a contact point, the situation that the outer side of the circular pipeline slides easily due to vibration isprevented, and cutting unevenness is avoided.