To achieve a laser capable of functioning in applications such as distance measurement and target designation, two methodologies were primarily utilized: The simulation analysis of the ray transfer matrix for the telescope cavity and the theoretical calculation of steady-state thermal resistance to analyze both the internal heat transfer and surface heat dissipation processes. Through rigorous theoretical examination and empirical validation, a compact solid-state electro-optical Q-switched air-cooled near-fundamental mode laser capable of operating at an ambient temperature of 40 ℃ was successfully developed. Output laser at 1064 nm was characterized by a repetition rate of 10 Hz, a single pulse energy of 100 mJ, a beam quality factor M² of 1.31, a pulse duration of 10 ns, and a divergence angle of 0.6 mrad. The findings demonstrate that this laser is optimally suited for applications that demand lasers with high single-pulse energy, peak power, and exceptional beam quality, such as in laser ranging and targeting. This advancement holds significant implications for the evolution of laser-based distance measurement and target indication technologies.