The work aims to extract agricultural heritage genes and introduce them into the destination tourism service design, propose differentiated positioning of tourism for the agricultural heritage destination, and improve the effectiveness of tourism service design. With Xiaozhan Town in Tianjin as a case, the agricultural heritage genes of Xiaozhan Town were extracted by gene mining. Based on the service design theory, the experience pain points and opportunities were summarized according to the user experience map, and the overall service design framework was clarified combined with the results of the service blueprint. There are three agricultural heritage genes in Xiaozhan Town, including farmland scenery genes, soldier and rice culture genes, and historical heritage genes. With gene-centric principles, the whole service design was proposed, integrating online service platform design based on virtual tourism with on-site service design centered on agricultural heritage. The findings are beneficial for enhancing the service experiences and promoting the sustainable development of agricultural heritage tourism in Xiaozhan Town.