In this study basic research was carried out to obtain the fundamental data of the needle-free injection system with powder injection. Improved needle-free injector was designed and manufactured. In addition, we measured the velocity of the powder particles, this was performed by simply visualizing the macro mode traveling at supersonic velocity to measure the number of milliliters of the square particles with high spatial and temporal resolution using high-speed video camera. The velocity data were acquired by the particle tracking velocimetry method after image processing.