The transversal parasitic oscillation characteristics of Fe2+∶ZnSe laser operating at room temperature are theoretically analyzed, and the results show that the population inversion threshold of parasitic oscillation can be effectively increased via the decrease of pump spot size, and thus the transversal parasitic oscillation of Fe2+∶ZnSe laser can be effectively suppressed. The experimental setup of Fe2+∶ZnSe laser end-pumped by a non-chain pulsed hydrogen fluoride (HF) laser is established. By inserting irises with different apertures, the output characteristics of Fe2+∶ZnSe laser are experimentally studied under different pump spot diameters. The experimental results show that, as for a Fe2+∶ZnSe crystal with end size of 20 mm×20 mm, the phenomenon of transversal parasitic oscillation can be effectively suppressed when the pump spot diameter is smaller than 9.2 mm，which is consistent with the theoretical analysis result. At room temperature, the maximum Fe2+∶ZnSe laser pulse energy that one can obtain is 136 mJ, the slope efficiency is 33.2%, and the optical to optical efficiency is 26.5% relative to the pump light energy.