The invention discloses a mono-dynamics bidirectional drilling mixing pile machine, comprising a forward rotating drilling rod, a reverse rotating drilling rod, an electric motor, a framework, a mixing can, a slush pump, bit blades, and a cyclic gear train mechanism for changing directions of the forward rotating drilling rod and the reverse rotating drilling rod. The cyclic gear train is disposed on the upper portion of the drilling rod. A fixation plate for changing the cyclic gear train to an ordinary gear train is fixed on the upper portion of the mixing pile machine which does not rotating with the electric motor. The invented method implements forward and reverse bidirectional drilling and mixing of the pile machine without changing structure and operation method of the traditional mixing pile machine; and the piling speed and piling quality are enhanced.