Abstract: The present disclosure relates to an injectable lurasidone suspension and a preparation method thereof, and in particular to an irregular form of a lurasidone solid and a pharmaceutical composition thereof. The present disclosure also relates to a preparation method for the solid and the pharmaceutical composition thereof, and an application thereof in the treatment of mental diseases. According to the present disclosure, the lurasidone solid prepared has controllable particle size and has Dv5O particle size of 6 ?m to 110 ?m. The good particle size stability can also he maintained in the pharmaceutical composition. The lurasidone suspension preparation obtained by the method is fast-acting, has a long sustained release period, and can effectively reduce the risk caused by poor patient compliance.