Abstract: As electronic countermeasures continue to evolve, passive time difference of arrival positioning has garnered extensive research and application due to its advantages of strong survivability, long detection range, and high positioning accuracy. The precision of time difference measurements is a critical factor directly influencing positioning performance. To improve the accuracy of time difference measurement of system, it is essential to correct errors caused by atmospheric refraction effects. However, atmospheric parameters, such as humidity, temperature, and pressure, vary with seasons and regions, and the atmospheric refractivity, as a function of humidity, temperature, and pressure, also varies accordingly. Obtaining accurate and real-time atmospheric refractivity requires additional equipment, thereby increasing development costs. In this paper, the impact of atmospheric refractivity on correction values in different seasons and regions, as well as the differences in correction values across different periods are analyzed by starting with the principle of passive time difference of arrival positioning and combining it with the methods of atmospheric refraction correction. The impact of these differences on positioning accuracy are theoretically analyzed, and the corresponding implementation measures for different engineering applications are provided.