Sewage treatment complexing agent as well as preparation method and application method thereof

The invention provides a sewage treatment complexing agent as well as a preparation method and an application method thereof. The sewage treatment complexing agent comprises components in percentage by weight as follows: 60%-80% of a main agent, 10%-25% of a pH regulator, 5%-10% of a proportion increasing agent and 2%-6% of an adsorbent, wherein the main agent comprises at least one of aluminum sulfate, sodium carbonate and quicklime. The preparation method of the complexing agent comprises the following steps: the components are weighed respectively according to the formula of the sewage treatment complexing agent, and mixing treatment is performed to obtain the sewage treatment complexing agent. The sewage treatment complexing agent has high flocculation and sedimentation speed as well as high turbidity removal rate, can purify water efficiently, is pollution-free for natural environment and is applied to sewage treatment and landfill leachate treatment.