During the highway construction, forest ecosystems are usually fragmented, leaving numerous bare cut slopes. External-soil spray seeding (ESSS) is widely utilized to restore these slopes, but our understanding regarding soil fungal communities during such a process still limited, particularly across an altitude gradient. Using high-throughput sequencing technology, we investigated the spatial shifts in the composition, diversity, molecular ecological network and assembly processes of fungal communities in both natural forest (NS) and cut slope (CS) along an altitude gradient. Results revealed significant differences in both the β-diversity and composition of fungal communities between CS and NS at each altitude site. The relative abundances of Ascomycota in CS decreased with the altitude, while those of Basidiomycota showed an opposite trend along the altitude gradient. Network analysis indicated a lower stability of fungal networks in CS than NS. Deterministic and stochastic processes jointly drive fungal community construction, with stochastic processes playing a major role. The construction of the fungal community is significantly correlated with soil pH and NH 4 +-N. This study improves our understanding about how soil fungal communities are restored in cut slopes in subalpine forests across altitude gradients. It also provides critical scientific guidance for restoring ecological functions on cut slopes formed during infrastructure development in forests.