The invention provides a preparation method of an environment-friendly water-saving fracturing liquid. The fracturing liquid is composed of a thickening agent and fracturing water, and the thickening agent is composed of the following components by weight: 30 to 80 b of chelating agent, 1 to 6 b of low-carbon alcohol, and 6 to 64 b of purified water, wherein the b represents a weight unit; the fracturing liquid comprises 100 c of fracturing water, wherein the c represents a volume unit, and the volume of the thickening agent is 1.0 to 10.0% of the volume of the fracturing water. The thickening is prepared by the following steps: preparing the raw materials according to the weight ratio mentioned above, adding purified water into a container with a stirrer, starting the stirrer, adding a chelating agent, fully stirring to dissolve the chelating agent; then respectively adding low-carbon alcohol and a chelating biological surfactant into the container, stirring for at least 30 minutes, allowing the container to stand still for a while until the solution is transparent, and storing the solution for later use. When the fracturing liquid is used, a thickening agent is added into a sand-mixing tank, wherein the volume of the thickening agent is 1.0 to 10.0% of the volume of water in a fracturing sand-mixing vehicle; and thus the fracturing liquid is formed in the sand-mixing tank by mixing the thickening agent and the fracturing water and can be used for fracturing construction.