The invention discloses a rocket and an assembly method thereof, and belongs to the technical field of aerospace. The rocket and the assembly method solve the technical problems of slow assembly, slowresponse and high cost of existing rockets. The rocket comprises a fairing, an effective load, a load supporting and releasing system, a flight control electric system and a power system, wherein thefairing is a shell; the effective load, the load supporting and releasing system and the flight control electric system are detachably arranged in the fairing in proper sequence; the flight control electric system is detachably connected to the power system; and the power system comprises a third-stage engine, a second-stage engine and a first-stage engine which are detachably connected in propersequence. The rocket is simple in structure, has high reliability, good safety, fast response and low cost.