The invention discloses a concrete-filled steel tube digging filling composite micro pile which comprises a filling pile hole located at the upper end inside a foundation and multiple micro pile holeslocated at the lower end inside the foundation. A concrete digging filing pile is arranged in the filling pile hole and comprises multiple first steel tube fine stone concrete micro piles arranged atequal intervals along the circumference and concrete poured in the space among the multiple first steel tube fine stone concrete micro piles. Multiple second steel tube fine stone concrete micro piles are arranged in the multiple micro pile holes. The multiple first steel tube fine stone concrete micro piles are coaxially and fixedly connected with the multiple second steel tube fine stone concrete micro piles correspondingly. The structural rigidity is large in top and small in bottom, stress is safe, the requirements for pile foundation structural strength and long-term stability are met, construction quality is high in controllability, influences on environment are small, and economical efficiency is better.