Electro-optics effects are important branches of nonlinear optics. In this project olive oil has been chosen to study its electro optical properties. These properties used in one of photonic applications that is optical switching. Olive oil as an organic compound has Centro symmetric molecular structures which mean that it has quadratic electro optical properties represented by Kerr effect. These electro optical properties such as transmittance versus applied voltage and birefringence versus the square value of the applied electric field were measured. These properties are obtained for the two types of olive oil (virgin and refined).by analyzing of these properties, the Kerr constant and Kerr coefficient for two types of olive oil have been found at different wavelengths which are 17.526×10-12(m/v2) and 7.3773×10-18 (m2/v2) for virgin olive oil at 660 nm and 18.603×10-12(m/v2) and 7.8306×10-18 (m2/v2) for refined olive oil at 660 nm and 19.860×10-12(m/v2)and 6.6239×10-18(m2/v2) for virgin olive oil at 532 nm and 21.4×10-12(m/v2) and 7.1375×10-18 (m2/v2) for virgin olive oil at 532 nm. This value of Kerr constant is useful to achieve a design for the total internal reflection switch using refined olive oil specially that material has a nematic liquid crystalline behavior.