Resource block management for network optimization is necessary in order to minimize interference, thus improving network performance. In a heterogeneous network where the femtocells are deployed inside a macrocell, the co-tier and cross-tier interference are still an issue in this research area. This interference can lead to degradation of the system performance. A proper resource block management is then required to reduce the interference. Several studies to reduce the interference have been conducted using various optimization methods, such as discrete bacterial foraging optimization (DBFO) and random scheme. However, interference reduction using a modified discrete mothflame optimization algorithm (DMFO) method has never been carried out before. Thus, a DMFO algorithm, which is one of nature-inspired algorithms, has been proposed to solve the resource block allocation problem. A heterogeneous system model combined with the DMFO algorithm has shown some significant acceleration. Compared to the DBFO and random scheme, DMFO was found to yield a better performance as proven by cumulative distribution function (CDF) of signal to interference noise ratio (SINR) graphic.