The invention provides a first-order phase-transition La(Fe,Si)13-based magnetocaloric material showing small hysteresis loss, and preparation and use thereof. The material has a NaZn13-type structure, is composed of granules with a particle size in the range of 15˜200 μm and not less than 15 μm, and is represented by chemical formula La1-xRx(Fe1-p-qCopMnq)13-ySiyAα. The method for preparing the material comprises steps of preparing the material La1-xRx(Fe1-p-qCopMnq)13-ySiyAα by smelting and annealing; and then crushing the material into powder with a particle size in the range of 15˜200 μm. Without changing the components, a La(Fe,Si)13-based magnetocaloric material showing small hysteresis loss and strong magnetocaloric effect can be obtained by adjusting the particle size within the range of 15˜200 μm. Utilization of this type of materials in the practical magnetic refrigeration application is of great significance. When the particle size is 10 μm or less, the stability of the magnetocaloric material is lost; the magnitude of magnetic entropy change is reduced dramatically; and thus it is no longer suitable for the practical application in magnetic refrigeration technology. Therefore, the giant magnetocaloric effect of the material can be maintained to the max if the granules with a particle size of less than 10 μm are removed by screening.