The present invention relates to a capacitive-coupled plasma processing apparatus, wherein an electric field regulating element, i.e., an “electric field lens”, is arranged in the reaction chamber to generate a regenerated electric field in a direction opposite to that of the original radio frequency electric field in the reaction chamber, so that the non-uniformity of etching rate on the surface of the substrate of the plasma incurred by the original radio frequency electric field is decreased; and the electric field regulating element, i.e., the “electric field lens”, further decreases the equivalent quality factor Q value of the reaction chamber, expands the radio frequency band, and prevents high-voltage electric arcing. The present invention further provides a method for processing the substrate using the processing apparatus.