The invention discloses an additive for improving utilization ratio of silicon crystal line cutting mortar as well as a preparation method and application method of the addictive. The additive is composed of the following raw materials in percentage by weight: 50-96.5% of polyethylene glycol, 1-10% of penetrating agent, 1-20% of ether alcohol surfactant, 0.5-10% of extreme pressure resistant chelator and 1-10% of assistant detergent. The preparation method comprises the steps of weighing and mixing the raw materials. The application process comprises the following steps: 1. carrying out the first line cutting the mortar and recovering the mortar; 2. adding the additive: adding the additive to the recovered mortar after the first linear cutting based on the weight ratio of 1:100 plus/minus10, and then evenly stirring; 3. carrying out the second line cutting; and 4. carrying out the third line cutting and recovering the mortar. The addictive is reasonable in design and has good use effect and practicable value, addictive preparation and use processes are simple, operation is convenient, and the defects of the existing silicon wafer cutting fluid such as more severe pollution, higher rejection rate, high production cost, low utilization ratio and the like can be overcome.