Based on the principle of fiber-capacitance liquid drop analysis metho d,the relationship between optical fiber signal and salinity in the water is a nalyzed,and the feasibility of salinity detection is studied.The relation exp re ssion between optical fiber signal and refractive index in the water is deduc ed by u sing Fresnel formulae.The changes of optical fiber signal caused by different s alinities are calculated according to the relationship between salinity and inde x in the water and the corresponding data table.The experimental device is establi shed and 20kinds of solution with different salinities are tested.The optical f iber liquid drop fingerprint and volume-based fiber drop trace of 20different s alinities are obtained.The experimental results show that the optical f i ber signal intensity increases with the increase of salinity in the water.F inally,the salinity detection relation expression with linear and quadratic polynomial is established by using four drops of complete liquid droplet′s optical fiber sign al mean values.By comparing two kinds of salinity detection models′ errors,the res ul ts show that the linear detection model has smaller error and better result,and the maximal detection error is 0.37%.