The resonance Raman effect is produced in a liquid core optical fiber. The Raman spectra intensity can be increased by 10 9 times. The resonance Raman spectrum of β carotene in CS 2 has been obtained. The concentration is 9.6×10 -12 mol/L. The laser power is 60 mW. The optical fiber length is 2.23 m, the inside diameter of the hollowcore optical fiber is 200 μm. In experiment we have found that frequency deviation of Raman spectra shifts when the concentration of β carotene in CS 2 is lower.