Optical light guiding capillary is used for evanescent wave absorption spectroscopy due to its unique geometry, consisting of hollow center surrounded by fused-silica capillary core, doped-silica cladding, and polyimide protection coating, respectively. Capillary guides light in the wavelength region from UV to near infrared through the wall of the capillary allowing long pathlength, small sample requirement, and direct contact of sample with a sensing area. Here, we report fabrication of a plasmon capillary by plating gold on inner wall of the optical capillary using an electroless gold plating method. Uniform gold deposition occurs over the entire inner core surface where propagating light induces surface plasmon resonance (SPR). Effects of silica core size, and plated gold thickness are examined to maximize the SPR response. Amplitude, breadth and red-shift of absorbance spectra are characterized for liquid and gas samples. Fundamental data in this study are applied to applications in chemical sensing and optical microfluidic heating.