The invention discloses a diatomaceous earth plastering material for outdoor walls. The diatomaceous earth plastering material for the outdoor walls is prepared from, by weight, 50-100 parts of diatomaceous earth, 20-40 parts of fly ash, 5-15 parts of nanometer cobaltous oxide, 5-15 parts of nanometer zinc oxide, 5-10 parts of carbon fiber, 4-8 parts of pigment, 20-30 parts of shell powder, 10-20 parts of acrylic acid modified resin, 15-20 parts of coconut shells, 8-15 parts of waste rubber, 10-20 parts of rubber oil, 5-10 parts of attapulgite, 24 parts of sodium dodecylbenzene sulfonate, 25 parts of sodium alga acid, 58 parts of sodium methyl silicate and 38 parts of cross-linked starch. The diatomaceous earth plastering material for the outdoor walls is good in compactness and film-forming property, achieves the moisture-proof, mildew-proof and air-purification effects, can prolong the time for protecting the walls, is low in cost due to the utilization of the raw materials, such as the waste rubber, the fly ash and the coconut shells, and is environmentally friendly due to the utilization of the waste.