  Linear alkylbenzene (LAB) is adopted to be the organic solvent for the
Jiangmen Underground Neutrino Observatory (JUNO) liquid scintillator detectors
due to the ultra-transparency. However the current Rayleigh scattering length
calculation disagrees with the measurement. The present paper for the first
time reports the Rayleigh scattering of LAB being anisotropic and the
depolarization ratio being 0.31+-0.01(stat.)+-0.01(sys.). We proposed an
indirectly method for Rayleigh scattering measurement with
Einstein-Smoluchowski-Cabannes formula, and the Rayleigh scattering length of
LAB is determined to be 28.2+-1.0 m at 430 nm.
