Spectral reflectance of targeted object is considered a vital inherent physical property in underwater spectral detection. However, the underwater environment poses significant challenges in spectral detection through strong absorption and scattering effects of light. To explore the influence of water turbidity on the accuracy of spectral detection, this paper describes the spectral reflectance detection under varying turbidity. Underwater spectral imaging system based on liquid crystal tunable filter (LCTF) is used for experimentation. Results proved that the increase in turbidity will further enhance the scattering intensity of water body. Based on the nonlinear increase in the pixel response of black and white board, the rapid upsurge in scattering intensity between 400–500 nm is noticed. Simultaneously, the spectral reconstruction method is applied, which yielded in maximum absolute error of 5.3% for spectral reflectance under different turbidity conditions.