Abstract: Attenuation characteristics of lightning electromagnetic waves during propagation are critical physical processes that affect the performance and accuracy of lightning detection systems. To improve the precision of lightning current inversion and enhance the reliability of lightning detection networks, the attenuation behavior of such pulses over medium-to-long propagation distances needs to be systematically characterized and quantitatively described. The study focuses on natural lightning events recorded on 4 April 2024, at the Jiuxian Mountain Observation Base in Fujian, China. Utilizng Hybrid Lightning Sferic Array, analysis is conducted on 31 negative cloud-to-ground return strokes observed synchronously over distances ranging from 200 km to 800 km, with particular emphasis on the amplitude attenuation characteristics of their low-frequency/very low-frequency (LF/VLF) electromagnetic pulses. To ensure the reliability of analysis, the equal-distance lightning event comparison method is employed to calibrate the relative station gains of seven selected observation sub-stations. This approach effectively eliminates instrumental biases, ensuring that the observed amplitude differences primarily reflect genuine propagation path effects. Based on the calibrated amplitudes, statistical fitting is performed to derive the propagation attenuation curves for these return strokes. Results indicate a significant power-law attenuation relationship between the amplitude of return stroke electromagnetic pulses and the propagation distance. The attenuation exponent for individual return strokes ranges from 1.10 to 1.20, with an average value of 1.16 for all 31 events. The goodness-of-fit for all curves exceeds 0.98, confirming the high reliability of this relationship. Furthermore, a detailed analysis is conducted on underestimation ratios in current inversion under different assumptions regarding the attenuation exponent. Results show that, even after distance-based attenuation correction, uncertainties in the attenuation exponent introduce additional errors into the inversion outcomes. Specifically, the underestimation of current varies systematically with both propagation distance and the chosen attenuation exponent, underscoring the importance of accurately characterizing attenuation characteristics for reliable estimation of lightning intensity. These findings hold significant implications for operational lightning detection networks, as inappropriate attenuation correction may lead to systematic biases in reported lightning peak currents. This investigation provides crucial observations for understanding the propagation mechanisms of lightning electromagnetic pulses in 200-800 km range. Results suggest that applying the average attenuation exponent of 1.16 for propagation correction can effectively reduce systematic errors induced by neglecting ground conductivity effects. This approach significantly enhances the accuracy and reliability of lightning discharge intensity inversion and offers valuable references for the calibration and data interpretation of operational lightning location networks.