Abstract: With one year of radiosonde observations as reference,the precision of GPS radio occultation (RO) atmospheric parameter profiles,including refractivity profiles,temperature profiles and pressure profiles,in four different austral seasons are compared and analyzed at 0～30 km altitude.We found that in average,the precision of RO profiles is worse in the austral spring than in the other three seasons.But in different altitude regions,the precision of RO profiles varies greatly.Generally,RO profiles are more precise at 5～25 km than at 0～5 km and at 25～30 km.In the lower troposphere of 0～5 km,the precision of RO refractivity profiles is the worst in the austral Summer and best in the austral winter.This is that the water vapor content in the atmosphere is the highest in summer and is the lowest in the winter.Above 5 km,the precision of RO pressure profiles is the highest in the Austral summer.The precision of RO temperature profiles doesn't vary much in different seasons and in different altitude regions.