To simultaneously detect salinity and depth without temperature interference, a salt depth sensing system based on different packaged fiber sensors was designed. Three different packaging forms of fiber sensors are connected in series to achieve calculation of salinity depth and temperature. Constructed inversion models for salinity and depth, and analyzed the feasibility temperature compensation. The experiment tested the changes in salinity, depth, and temperature separately. The results showed that in the salinity test of 0～50 g/L, the average sensitivity of the system was 128.7pm·g^-1·L^-1, and the linearity of the wavelength shift between the main peak and the first main peak of salinity change was 0.9654. In the depth test of 1~15 cm, the average wavelength shift with depth is 751.9 pm/cm, and the linearity is 0.9931; In the temperature test of 23~45 ℃, the temperature response of the three fiber optic sensors was basically consistent. After temperature compensation using FBG2 test data, the wavelength deviation of LPG and FBG1 was only ±10 pm.