The invention discloses a polyvinyl chloride drain pipe and a preparation method thereof. The polyvinyl chloride drain pipe comprises the following raw materials in part by weight: 100 parts of polyvinyl chloride, 30 to 100 parts of hollow glass microsphere processed by coupling agent, 0.5 to 5 parts of thermal stabilizer, 0.5 to 5 parts of lubricating agent, 1 to 3 parts of titanium dioxide, 0 to 10 parts of flexibilizer and 0 to 2 parts of processing agent. The method adopts the mode of plastic modifying, creatively introduces the hollow glass microsphere for filling, effectively improves the product toughness on the basis that the product rigidity is guaranteed, simultaneously effectively reducing noises through a hollow structure, greatly reduces the product density, reduces the product weight, and can also reduce the product cost.