Bose-Einstein condensate atoms with a ratchet potential appear regular and chaotic distribution. By using equivalent potential and the direct perturbation method obtains the chaotic solution of the condensed system. Further investigates the influence of the nonlinear interaction between BEC atoms on the distribution of the condensed system, and finds the conclusion that the stronger nonlinear interaction can cause the system atoms from regular distribution transforming into chaos distribution. Numerical simulation also reveals that the regular and chaotic distribution of BEC atoms can be controlled by adjusting the ratchet potential strength.