We introduce a self-questioning mechanism under spatial public goods game in the framework of Evolutionary Game Theory where players are located on a square lattice and realize it by a intensity parameter a. By stimulation and analysis, we find that compared with the original Fermi updating (a=0), the introduction of the self-questioning (a>0) can be better promote cooperative behavior at the smaller r. Subsequently, we stimulate in self-questioning mechanism (a=1), the cooperator frequency fc as a function of the factor r for different values of noise K. Results show that at the larger and smaller noise K, the system presents a considerably different cooperation phenomenon. Whats more, fc as a function of r has center symmetry nature about point (5.0, 0.5) whatever the noise K is. Further analysis indicates the reasons for the formation of these phenomena. Finally, we report the agents average payoff in the steady state and its reasons for it.