A general power quality measuring system based on virtual instrument (LabVIEW) has been developed. For two electric railway traction transformers of Zhengzhou-Xi’an High Speed Passenger Dedicated Line, which access to Zhengzhou, Henan Grid, some important power quality parameters have been measured and analyzed. Then, the analysis results are compared with the calculation results by Power System Harmonic Penetration Software (PSHP), which is developed by our group. It shows that real measured data of Harmonic Ratio and Three-phase Unbalanced Factor of electric railway traction substations is comparable well with the calculation results. Furthermore, Three-phase Current Unbalanced Factor accorded well with the theoretical value of the V/v-connected traction transformer, and Total Voltage Harmonic Distortion and Unbalanced Factor meet the requirements of relative national standard.