The invention belongs to the technical field of mine filling, and particularly relates to a pumping agent for improving the mobility and the stability of full-tailing pasty fluid cementing filling slurry and an application of the pumping agent. The pumping agent is prepared by mixing polycarboxylate-type super plasticizer powder, air entraining agent powder and tackifier powder, wherein the mass ratio of the polycarboxylate-type super plasticizer powder to the air entraining agent powder to the tackifier powder is (0.3-0.8): (0.025-0.075): (9.675-9.125). The pumping agent, the mass of which accounts for 10% of the mass of the total solids, is added to the full-tailing pasty fluid cementing filling slurry for use. After the pumping agent is added to the slurry, the solid concentration and the viscosity of water are improved, tailing fine particles and a cementing agent are uniformly distributed in the slurry, the pasty fluid cementing filling slurry is not separated, bled and leaked in a filling zone, and the consumption of the cementing agent is greatly reduced. The pumping agent has relatively good environmental benefits and economic benefits.