The time sequence design of the Lband Upperair Sounding System is analyzed. GTS1 Sonde and RS92 Sonde are compared to determine the time difference between the sensing meteorological elements and the time of the ground equipment caused by the Lband Upperair Sounding System will cause the uncertainly of the measurement results. The influence of time difference on pressure is larger, the temperature is smaller, and humidity is more complex. The uncertainty of air pressure will affect the accuracy of sounding application files. The sensing time is always delayed relative to the measuring element, which is about 1.2 s after the measuring element senses the meteorological elements. The time difference is about 0.98 s. The maximum pressure error is up to 0.86 hPa. The BDSGPS Dualmode Navigation Wind Sonde is designed to eliminate the time difference and significantly reduce the random error of the measurements. It has a good effect on the Yangjiang test conducted by the China Meteorological Administration in December 2013, which proposed an improved method.