The invention discloses an integrated composite spray pipe based on gradient materials. The materials and components of the spray pipe change from the outer wall to the inner wall of the spray pipe ina gradient mode, and the spray pipe comprises a supporting layer, a thermal insulating layer and an ablation resistant layer which are distributed and connected from the outer wall to the inner wallof the spray pipe in sequence. Functions of a ceramic matrix composite of the ablation resistant layer, a low-thermal-conductivity thermal insulating material of the thermal insulating layer and a metal matrix composite of the supporting layer are organically integrated, assembling weak interfaces between the materials of all the layers are eliminated, the mutual coupling effects between the materials of all the layers are enhanced, the design weight of the spray pipe is brought into play to the maximum extent, accordingly, a light weight is achieved, and meanwhile, the structural reliabilityof the spray pipe is also greatly improved after assembling macroscopic interfaces between all the layers are eliminated.