Abstract: The single event upset (SEU) of low-Earth-orbit (LEO) satellites has a great impact on the lifetime and the reliability of the in-orbit satellites. But the in-orbit verification results are few for the SEU of the internet satellite at a typical polar orbit altitude in the range of 1000 km to 1200 km. This paper analyzes and processes the SEU record data of the two satellites in-orbit for seven months, and gives the frequency, the area and the orbital heights of SEUs at different orbital altitudes from 1050 km to 1425 km for the internet satellites. It is shown that the probability of the in-orbit SEU for the onboard SRAM is about 7.63×10^-7 bit^-1·d^-1, and most in-orbit single event upsets occur in the South Atlantic Anomaly (SAA) area. And it is shown that the reliability of the LEO internet in-orbit satellites can be effectively improved by strengthening the control of the component selection, the software and hardware redundancy design and the current limiting of the key components.