A microfluidic chip device was developed for rapid and automatic particle sorting. The chip was made up of six individual layers. Each layer was used to implement different functions such as the sample loading, electric voltage loading, optic detection, cell sorting, and product extraction. Sheath flow was used to form single-row cells in order to let cells flow through the optic detection zone one by one. Optic fiber based detector could distinguish particles with different sizes. When a particle flowed through the light beam between two opposite optic fibers, it induced the dispersion of the incident light. The size of the particle was related with the strength of the scattering light. Thus, different particles could be distinguished. In the detection method, light path was simple and label was not required. Furthermore, optic fiber based detector was helpful to decrease the volume of the whole system. When desired particle was detected, it would be separated in the downstream by using an electric deflection method. Two types of particles with different sizes were sorted by using a prototype device. The result showed that these particles could be obviously distinguished. This microfluidic system could also be used to sort biological cells. Instantaneous electric field on the cells could prevent cells from severe injuries.