The invention discloses a biodegradable water-based type metal cleaner which is prepared from the following components in parts by weight: 4 to 60 parts of surface active agent, 0.1 to 5 parts of rust-proof corrosion inhibitor, 0.1 to 5 parts of complexing agent, 0 to 10 parts of detergent assistant, 0 to 10 parts of cosolvent, and 30 to 85 parts of water. The surface active agent is prepared fromthe following components in parts by weight: 1 to 20 parts of fatty acid methyl ester ethoxylates, 1 to 20 parts of grease ethoxylate, 1 to 10 parts of natural fatty alcohol polyoxyethylene ether sodium sulfate, and 1 to 10 parts of alcohol alkoxylate. Compared with a conventional surface active agent, the biodegradable water-based type metal cleaner provided by the invention is easy to biodegradable, has high permeability and cleaning capacity, has an outstanding solubilization effect on oily dirt, has high degreasing efficiency on metal without corroding the metal surface, has excellent biodegradability, and is capable of effectively reducing the pollution of degreaser waste water on the environment.