One-dimensional spatial distribution of the plasma luminous radicals during depositing silicon films and its online monitoring were studied using optical emission spectroscopy. The results indicated that there existed an evident luminous zone in the middle of the plasma and a dark zone near the two electrodes. The intensity of SiH* and Hα* peak increased with the increase of silane concentration, power, and the incorporation of borane. Crystalline volume fraction of thin films decreased with the increase of borane flow rate, but the ratio of I［Hα*］/I［SiH*］ was also increased. The ratio of I［Hα*］/I［SiH*］ varied in different ways at different positions with the variation of silane concentration. However, an unigue variation of the ratio all over the plasma is observed with the variation of the discharge power or the borane flow rate.