The invention relates to an excavation construction method of an ultra-shallow buried uneven weathered stratum of a tunnel. A segmented step method is used for construction, and a tunnel section is divided into a left side of an upper station, a right side of the upper station, a middle station and a lower station; each segment of step is sequentially constructed circularly, one-time excavation length of each segment of step is not larger than 30m preferably, and a middle partition wall is changed into a straight wall from the traditional curved wall at the left side of the upper station. Thus, for the uneven weathered stratum in the shallow buried area of wall rocks, the dynamic construction method using the segmented step method has little process interference, reduces the construction cost, has simple operation, safety, reliability, less temporary support, low fund investment and high construction speed, is suitable for large machinery for construction, and ensures that the whole construction process is in a safe, stable, high-quality and high-speed controllable state.