Knowledge of distribution of atmospheric optical turbulence in propagation path is indispensable to evaluate the optical propagation effects accurately. Vertical profiles of optical turbulence strength are obtained from balloon flights. The data are decomposed into intrinsic mode functions on different scales by ensemble empirical mode decomposition. The quasi-cyclical variations on different components as well as their contribution to entire profile are analyzed. The results show that the cyclical scale within some intrinsic mode components is confirmed passing the statistical significance. Variance contribution rates show that the overall trend and stochastic intense noise are the main cause for the optical turbulence variation. A signal-filtering method based on consecutive mean square error is used to separate the profile into background and stochastic term. Correlation analysis of background and statistical mean show that the correlation coefficient is larger than 0.99. Analysis of stochastic term indicates that the optical turbulence profile is nonstationary series with multifractal structure.