The invention discloses a synthesis method of SnS crystals shaped like a letter C. The synthesis method comprises the following steps that 1, a tin-containing precursor, a sulfur-containing precursor and a surfactant are dissolved into water to prepare a solution, wherein the surfactant is polypyrrolidone; 2, the solution prepared in the step 1 is transferred into a reaction kettle and heated, after full reacting is conducted, centrifuging is conducted, samples are washed with water and alcohol, and the SnS crystals shaped like the letter C are prepared. The synthesis method has the advantages that a technology is simple, the production cost is low, and the prepared SnS crystals shaped like the letter C are uniform in morphology, suitable for being used for directly preparing a lithium battery electrode material and a solar cell and easy to apply and popularize.