Spectral line broadening is calculated based on a microscopic quantum statistical approach. By using thermodynamic Green's function, plasma correlation effect, electrostatic and dynamic screening, and perturber-radiator interaction are taken into account. Ions are treated in quasistatic approximation due to Stark effect. The line broadening
for 6678 Å (21P-31D) and
5016 Å (21S-31P) transitions of neutral helium is calculated in the electron density range ne=(0.25–50)×1022 m-3 and temperature range T=(0.5–4)×104 K, and the density and temperature dependence of the line width are investigated. A good agreement is shown by comparing the calculated values with the existing experimental and theoretical data.