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Weighted mean temperature (Tm) is a critical parameter in Global Navigation Satellite System (GNSS) technology to retrieve precipitable water vapor (PWV). It is convenient to obtain high-precision Tm estimates near surface utilizing Bevis formula and surface temperature. However, some researches pointed out that the Bevis formula has large uncertainties in high-altitude regions. We investigate the applicability of the Bevis formula at different height levels and find that the Bevis formula has relatively high precision when the altitude is low, while with altitude increasing, the precision decreases gradually. To solve the problem, we analyze the relationship between Tm and atmospheric temperature within the near-earth space range (the height range between 0~10km) and find that they have a high correlation on a global scale. Accordingly, we build a global weighted mean temperature model based on near-earth atmospheric temperature. Validation results of the model show that this model can provide high-precision Tm estimation at any height level in the near-earth space range.