The invention discloses a quantitative evaluation system and method of a crude oil emulsion stability. The system comprises a signal generator, an oscilloscope, a voltage amplifier, a bottle-test type demulsification dehydrator, a constant-temperature water bath, an emulsion test bottle, a kinetic stability analyzer and a computer, wherein the signal generator generates electric signals with a specific waveform, voltage and frequency, signal amplification is performed through the voltage amplifier, and then an asymmetric high-intensity electric field is applied to crude oil emulsion in the bottle-test type demulsification dehydrator to enable water particles therein to produce electrostatic coalescence and further to accelerate gravity settlement; or under the situation that no electric field is applied, a demulsification agent is directly added into the crude oil emulsion in the bottle-test type demulsification dehydrator to perform chemical demulsification; quantitative analysis and evaluation are performed on the demulsification effect by calculating emulsion dehydration rate or by using the kinetic stability analyzer. The evaluation system and method are convenient, quick, accurate and reliable to use, and can provide convenience for evaluation work of the emulsion demulsification effect under various conditions in laboratories and engineering fields.