Abstract: Wind and wave growth is widespread in nature and industry. Due to the randomness and multi-scale characteristics of wind field and wave field, no reliable principles can be obtained through experiments to explain the mechanism. It is very necessary to study the generation mechanism of wind and wave evolution through detailed simulation. In this paper, a wind-driven free surface with a wind speed of 1.6 m/s is numerically simulated. The wave growth obtained consists of linear and exponential growth phases defined by the earlier theory. According to the wind and wave characteristics, as well as the two-dimensional wave number and the energy distribution in the frequency domain space, the mechanism characteristics of wind and wave growth in different stages are revealed. The mechanism characteristics of waves in different stages are revealed. It is observed that before exponential growth, the linear growth of waves has initial response stage, wind pressure stable stage and wind pressure disturbed stage, which have different mechanism characteristics respectively. The original Phillips theory is accurate only in the initial response phase of growth, and resonance enhanced theory is also consistent with the actual growth after the initial response. while the Miles theory is accurate only in the monochromatic wave phase.