The expression and accurate prediction of the ocean wave period is a knot. Factors affecting the wave period are often ignored in the simulation and there is no detailed analysis on influencing factors.The evolution characteristics of the wave period of deep-water breaking waves are experimentally studied. Deep-water breaking waves are generated by the method of energy focusing in a 2D wave flume and the intensity of wave breaking is toned by changing input wave amplitude.The spectral averaging period and the average period T and effective period TH1/3based on Zero-up crossing method are computed for surface elevations.It is concluded that the four kinds of spectral averaging periods are stable outside the focusing area.When focusing waves don’t break,the variation rate of wave periods is less than 1%.Breaking causes wave period’s increasing and the increment is more appreciable when the wave breaking is stronger.Through comprehensive analysis from the stability and the wave nonlinear mechanism,the variation of T0,2 along the flume could reveal the evolution characteristics of the wave period in the process of deep-water wave breaking.