A multi-curve petal truss structure and a construction method thereof. The truss structure is connected with a main body structure and comprises an annular truss located in the center, an internally-closed petal structure body which is annularly connected to the annular truss and an externally-released petal structure body which is annularly connected onto the periphery of the bottom of the internally-closed petal structure body. The internally-closed petal structure body comprises a set of internally-closed petals which are closed towards an inner ring of the annular truss, wherein at least two internally-closed petals are symmetrically closed on the inner side, and at least two internally-closed petals are symmetrically surrounded on the outer side. The externally-released petal structure body comprises a set of externally-released petals which unfold outwards and is connected with the main body structure through an externally-released petal stress truss. According to the multi-curve petal truss structure and the construction method thereof, progressive design in a layer by layer mode is adopted, the annular truss is designed firstly, then the internally-closed petals are designed, finally the externally-released petals are designed, progression is achieved layer by layer to form a complete spatial system, and structural stability is higher; and the installation sequence of the stress truss is reasonably arranged through the construction method, the positioning coordinate of the stress truss is reasonably controlled, and the overall stress requirements of the petal truss can be ensured.