The invention discloses an ejecting device for erection construction of a continuous beam. The device comprises M beam body ejecting mechanisms used for synchronously and horizontally ejecting beam bodies needing to be ejected, and n sets of vertical ejecting mechanisms used for synchronously ejecting the beam bodies needing to the ejected, the beam bodies needing to be ejected are the continuous beam erected on N permanent buttresses which are distributed on the same circular arc line C in the circumferential direction, and each beam ejecting mechanism comprises two horizontal ejecting and sliding mechanisms distributed in the tangent line direction of the circular arc line C and two correcting mechanisms used for carrying out left-and-right adjustment on the ejecting directions of the two horizontal ejecting and sliding mechanisms respectively. The device is simple in structure, reasonable in design, easy and convenient to use, safe and reliable in ejecting process and good in use effect. Meanwhile, an ejecting method for erection construction of the continuous beam is further disclosed. The ejecting method comprises the steps that firstly, preparation work before ejecting is carried out, and secondly, ejecting is carried out in multiple times in the time sequence. The method is simple in step, reasonable in design and convenient to implement, and the ejecting process is easy to control.