During the segmented multi-cluster fracturing process of land-phase shale gas horizontal wells, it is difficult to maintain the balanced expansion of each cluster of hydraulic fractures within the segment, and the ability of single-cluster fractures to penetrate through the formation is constrained, which leads to poor fracturing and reforming effects. In view of this, a set of numerical simulation methods for synchronous expansion of multi-cluster fractures in terrestrial shale horizontal wells was established, and a set of scientific and perfect optimization methods for the parameters of segmented multi-cluster fracturing in terrestrial shale horizontal wells were proposed with the objectives of single-cluster fractures penetrating through the high-quality reservoirs, balanced development of multi-cluster fractures, and construction pressure not exceeding the safe pressure limit. The results show that: the use of high-displacement and high-viscosity fracturing fluid is beneficial to the expansion of hydraulic fractures through the formation; the more clusters of holes in a single section, the more uneven the development of hydraulic fractures in each cluster; with the decrease of the number of holes in each cluster and the increase of the borehole molar resistance, the more even the development of hydraulic fractures in each cluster is; continuing to reduce the number of holes in each cluster has limited effect on the balanced development of hydraulic fractures and the excessive reduction of holes in each cluster will lead to the high pressure during the workover. Optimized design of fracturing parameters was carried out for one example well, which took into account the single-cluster fracture expansion and the balanced development of multiple clusters of fractures, and achieved a good effect of production increase. The results of the study can provide theoretical basis and optimization method for the optimization design of fracturing parameters of horizontal wells with multiple clusters in land-phase shale gas.