A liquid composition of an insoluble medicament and a preparation method thereof are disclosed. The composition includes insoluble medicament, oil for injection, phospholipid, and solvent; the percentage by weight of each component is as follows: insoluble medicament 0.01-10%, oil for injection 0%-20%, phospholipid 10-80%, solvent 20-89%. The preparation method for the composition includes the following steps: dissolving an insoluble medicament into solvent or oil for injection or a mixture thereof firstly, and then adding other components, and mixing uniformly; or dissolving an insoluble medicament into a mixture of other components, and mixing uniformly; or dissolving an insoluble medicament into part of solvent firstly, and then adding into a mixed solvent of other components and the remaining solvent, and mixing uniformly.