The invention discloses a water-collecting degradable mulching film, which comprises the following raw materials by weight: 100 parts of a degradable polymer, 0.5-3.5 parts of a hydrophobic agent, 2-5parts of a water-collecting agent and 0.5-2 parts of a tear-resistant agent. The mulching film contains the water-collecting agent and the hydrophobic agent simultaneously, the surface of the water-collecting agent is super-hydrophilic, can adsorb mist in the air and convert the mist into small liquid drops, and meanwhile, under the cooperation of the hydrophobic agent, the liquid drops cannot spread and stay at positions except the water-collecting agent, only can continuously enlarge in a spherical shape around the water-collecting agent, and then roll into soil under the action of gravity,thus realizing soil irrigation. Meanwhile, the water-collecting degradable mulching film provided by the invention has the characteristics of cheap raw materials and simple preparation process, and has great application value.