The invention relates to a method for preparing pharmaceutical cocrystals through suspension crystallization. The method concretely comprises the following steps: firstly screening solid forms of active pharmaceutical ingredients API and cocrystal formation CCF in different solvents, preparing a CCF saturation solution together with a solvent which cannot generate solvate together with the API and CCF; feeding the prepared CCF saturation solution into a vessel type stirrer, feeding the solid API and CCF according to a certain solid load rate, and deciding the ratio of molar weight of the API and CCF according to the cocrysal chemical metrological ratio; and sampling to do XRD or DSC testing after fully stirring and mixing, so as to prove that the cocrystal solid phase is pure, performing vacuum filtration to the obtained solid, and washing and drying the CCF saturation solution to obtain a solid, namely a final cocrystal product. Compared with other methods, the method is low in energy consumption, less in used solvent, low in cost, simple in technology, easy to amplify, fast and easy to obtain, high in the purity of products, and suitable for industrial large-batch synthesized pharmaceutical cocrystals.