The difference-frequency module serves as the core component of the tunable terahertz source, with its performance directly determining the efficiency of terahertz generation. To enhance the terahertz output power, this study designed laser beam reduction systems with 2:1 and 3:1 ratios based on laser parameters after optical power amplification. This ensures consistent beam diameters for optimized spatial mode matching. Through polarization calibration, the lasers maintain linear horizontal polarization to fully exploit the crystal's maximum nonlinear coefficient. Post-alignment, the dual beams achieve precise spatial overlap, forming a focused spot of approximately 22 μm after passing through the focusing lens, thereby significantly enhancing difference-frequency conversion efficiency. Experimental verification confirms that this module has successfully enabled terahertz wave generation.