The invention discloses a preparation method for a reticulate structural part provided with component and pore double gradient transition layers. The method comprises the following steps that (1) a three-dimensional model of a reticulate structure with bionic unit topology and gap dimension gradient changes is design, the three-dimensional model is subjected to slicing treatment and then converted into an STL document, and the STL document is input into SLM forming equipment; (2) various powders are evenly mixed according to a preset ratio, and a mixed powder is fed and laid; (3) a current slice layer of the reticulate structural part is subjected to laser scanning forming and is descended by the thickness of a laid power layer after forming is finished, and then the mixed powder in the current ratio is adopted for forming the next slice layer; (4) the step (3) is repeated until forming of the layers with the set height is completed through the powder in the current ratio, mixing of powder in another ratio is completed, and powder feeding and laying are conducted; and (5) the step (3) and (4) are repeated until forming of the whole reticulate structure with various components being in gradient transition is completed. The preparation method has the advantages of being high in preparation efficiency, simple in preparation technological process, low in cost and the like.