A schlieren visualization technique for high-enthalpy and low-density test flow using an LED light source is described. An LED driver circuit was designed and was confirmed its response characteristics. An optical band-pass filter was inserted in the schlieren optical setup to mitigate luminescence emissions of the test flow. The test results indicate that this schlieren visualization technique with the LED light source and the corresponding band-pass filter is feasible for hypervelocity test facilities with low cost. The flow field was numerically reproduced with CFD, which indicates a quantitative threshold level for the feasibility of schlieren visualization.