Silicone rubber (SIR) samples are exposed to CF4 capacitively coupled plasma (CCP) and inductively coupled plasma (ICP) at radio frequency (RF) power of 60–200 W for a treatment time up to 20 min, respectively. Static contact angle is employed to estimate the change of hydrophobicity of the silicone rubber modified by the two coupled types of CF4 RF plasma. A milder enlargement of static contact angle of SIR samples modified by ICP treatment is observed compared with that by CCP treatment. The hydrophobicity of the modified SIR surface by CCP treatment increases to a maximum, and further decreases toward the hydropholicity. The higher self-bias on the SIR samples being modified by CCP treatment than that by ICP treatment leads to the more dramatic physical and/or chemical reaction on the SIR surface, resulting in the competition between fluorination and ablation or etching.