The sequence of global earthquake magnitude of 7.0 and more than 7.0 is analyzed by the methods of Hurst exponent, fractal dimension D, correlation coefficient C and V-statistics and the scatter diagram and fitting trend line. The results show that this sequence is a fractional Brownian motion, mean reversion process (pink noise, anti-persistence and persistence against the state), and with a frequent reversal mutation or volatility. In the long case, the magnitude shows a very slight downward trend. Conclusion of the study can provide reference for seismic studies and safety studies.