The assessment of domestic scholars and WMO suggests that the GTS1 2 radiosonde needs technological improvement to meet the needs of operational upper air observation, which was conducted on the basis of original technical structure in 2012 and the improved radiosonde was temporarily named GTS1 2A. In August 2012, its test was carried out in the Yangjiang radiosonde station. The results show that it performed well in temperature measurement at night with system error less than-03 ℃ and overall standard deviation within 02 ℃; but in the daytime, except at upper levels and when in/out of clouds, overall its system error is-03 ℃ and its standard deviation is less than 04 ℃. As for pressure measurements, in the near surface layer, the system error is about-15 hPa, and its accuracy and stability are better than GTS1 2 Especially its standard deviation is less than 07 hPa within full range. Its humidity has good consistency with RS92 with sensitivity better than GTS1 2 and overall system error and standard deviation within 10%RH.