An orthogonal set of experiments was performed on common shotcrete, where the coarse and fine aggregates were substituted with ceramsite and pottery sand, while basalt and plant fibers were also added. The influence of ceramsite, pottery sand, basalt fiber, and plant fiber on the mechanical properties and thermal conductivity of shotcrete was investigated, and the relevant mechanisms were analyzed using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that the admixtures formed a stable state in the concrete matrix when the coarse and fine aggregates were substituted by 5 mass% of ceramsite and 10 mass% of pottery sand, respectively, and with 0.15 and 0.2 vol.% basalt fiber and plant fiber, respectively. At this point, the cement hydration was normal, and the strength of the concrete was relatively higher than other groups. The ceramsite and pottery sand formed a uniformly distributed porous structure in the concrete matrix, thereby reducing the thermal conductivity of the concrete.