Abstract: When integrating frequency domain resources in open-pit mines, the resource allocation process has static and fuzzy characteristics, resulting in low spectrum resource utilization efficiency in the communication environment of open-pit mines. There are problems such as low number of users allowed to access and low spectrum utilization rate. Therefore, a 5G based optimization model design for open-pit mine frequency domain fusion technology is proposed. By analyzing the frequency bands and transmission characteristics of the 5G open-pit mine frequency domain, the idle frequency bands in the frequency domain are calculated, and the total number of idle spectrum bandwidths across the spectrum is obtained. Based on the frequency domain requirements of different users, the frequency domain spectrum fusion priority level is calculated by the user’s location and frequency coverage distance, with the goal of optimizing the utilization rate of idle frequency bands while maximizing the number of users, to complete the frequency domain spectrum fusion of open-pit mines. The experimental results show that as the spectrum span increases, the number of allowed access users and spectrum utilization rate both increases, with the upper limit of spectrum utilization rate being about 97%. This model has demonstrated good performance and robustness in complex communication environments of open-pit mines.