A reliable content evaluation method and system are disclosed. The system includes a brainwave detector, a bio signal detector, a first controller, and a second controller. The brainwave detector detects a brainwave signal of a subject provided with content and outputs a result. The bio signal detector detects bio signals of the subject and outputs a result. The first controller can modify the brainwave and the bio signals to a signal level available for the second controller. The second controller detects change of the brainwave signal and the bio signal through an analysis of the brain wave signal and the bio signal from the first controller. Then, the second controller determines at least one of a degree of engagement and an emotional reaction of the subject to the content, using changes in the brainwave signal and the bio signal, and evaluates the content using the determined results.
