In order to cater to the demand of electric tool enterprises for brand recognition, the work aims to apply the principle of biological split gene transcription to the form design process of products to achieve iterative updates of electric tool products, establish product family features, and strengthen brand recognition. The fundamental genetic structure of the enterprise's target product family was analyzed, the outline of early product styling was extracted with graphic design software, and a genetic map of the product form was created. Based on the similarities between the splicing mechanism of split gene transcription and the form gene screening process in the iteration of electric tools, the design form analysis method and cluster analysis were used to categorize form genes into three types of typical genes, sub-typical genes, and general genes. The combination of typical genes and sub-typical genes formed the genetic framework of the product. With the genetic framework as a foundation and shape grammar as the deduction method, a genetic map of the form for guiding product iterations was created based on the established rules for brand feature recognition. Finally, the new and old genetic maps were evaluated and verified with the Likert scale. The design theory and method based on the principle of split gene transcription were proposed, and new form gene maps with recognizable family features were created by shape grammar. With the scroll saw design of the Dongda brand as an example, the new form gene map outperforms the old form gene map based on relevant statistical data obtained through the Likert Scale. The results validate the feasibility of this method.