Helium, as the simplest multi-electron atom, is a good testing ground to verify the difference between theoretical calculations and experimental measurements. As a consequence, helium plays an important role in the field of precision measurements. In this thesis, we built a stable metastable helium atomic beam system. Firstly, we will report how we designed this system and how it works. The metastable helium source is produced by radio frequency (RF) discharge excitation. We checked the stability by numerous measurements, and analyzed how argon mixture affects helium beam. Then we applied the crossed-beam method and observed the characteristics of atomic beam by detecting the fluorescence signal. The properties of atomic beam will all be studied in this thesis, including the influence of helium and argon pressure, speed distribution, divergence angle, number of atoms and atomic beam flux.