The invention relates to the technical field of pile foundation engineering, in particular to a truss type steel pipe grouting pile foundation and a construction method thereof. The pile foundation comprises one or more pile foundation units. Each pile foundation unit is composed of four vertical piles erected in a rock-soil body, wherein the four vertical piles are located at the four corners with square horizontal cross sections correspondingly, every two adjacent vertical piles along the corresponding edge of the square are connected through two oblique piles which are in an X shape, every two corresponding oblique piles intersect with each other, but the axes of the two corresponding oblique piles does not intersect; square connecting beams are arranged at the tops of the four vertical piles, and the vertical piles, the oblique piles and the connecting beams are connected to form a truss type structure; and acute angles or obtuse angles are formed between the oblique piles and the vertical piles rather than the oblique piles are perpendicular to the vertical piles. The invention further provides a construction method of the pile foundation. By the adoption of the truss type steel pipe grouting pile foundation and the construction method thereof, the overall rigidity of the pile foundation can be improved, the vertical bearing capacity and horizontal shear capacity of the pile foundation can be improved, and differential settlement of the foundation is reduced; and compared with a conventional straight pile foundation form, the truss type steel pipe grouting pile foundation has the advantages that the construction cycle is short, the construction cost is low, and construction is convenient.