This paper focuses on a fractal Phi-4 equation with time-space fractal
derivatives, though its solitary solutions have been deeply studied, its
periodic solution was rarely revealed due to its strong nonlinearity. Now
the condition is completely changed, He?s frequency formulation provides
with a universal tool to having a deep insight into the periodic property of
the fractal Phi-4 equation. The two-scale transform is used to convert
approximately the fractal Phi-4 equation to a differential model, and a
criterion is suggested for the existence of a periodic solution of the
equation, the effect of fractal orders on the periodic property is also
elucidated.