As surface plasmon resonance (SPR) spectrum is sensitive to refractive index of the mediums, we explored its sensitivity characteristic of ions composition detection in a solution so as to measure the total dissolved solid value in water. Seven ionic (NaCl, KCl, CaCl2, MgCl2, Na2CO3, MgSO4 and ZnSO4) and 3 non-ionic (glucose, glycerol and sucrose) liquid samples were studied experimentally with a fiber optic SPR sensor. The influence of ion concentration on the resonance wavelength shift in SPR spectrum was investigated and discussed, and with that, the response curves were established to realize the detection of total dissolved solid in water quality analysis. The FO-SPR sensor spectral curve for TDS measurement was in conformity with ionic conductivity in 8 different water samples, and results show that the spectral method was better in high ion concentration detection of water. This research will broaden the SPR application in the field of water quality monitoring.