The invention belongs to the technical field of tunnel and coal seam mining, and provides a controllable grouting liquid for coal mining and tunnel engineering and a preparation method thereof for solving the problems that the current grouting liquid is not easy to enter cracks and easy to block grouting holes and the like. The controllable grouting liquid is prepared by mixing ultrafine sulfate cement, redispersible emulsion powder, a high-efficiency water reducer FDN, nano-silica, calcined gypsum, alunite powder, lithium carbonate, wooden calcium and water according to in a certain ratio. The controllable grouting liquid has the advantages that raw materials are easy to obtain, the condensation rate of the grouting liquid is controllable, the workability is good, the pumping effect is good, the water repellency is low, the surface hardness is high, the later strength is stable and does not shrink, the production cost is low, the construction speed is high, the work efficiency is high, and the environment is protected. The grouting liquid can be effectively poured in micro-cracks, is capable of enlarging a grouting radius, and is of great significance for the rapid lining supportreinforcement of a tunnel and the pollution-free, safe and efficient mining of coal. With the adoption of the controllable grouting liquid, emergency rescue projects can be dealt with easily, the construction speed is high, the work efficiency is high and the construction time is saved.