The invention relates to a multiaxis creep test system achieving internal pressure and stretch combination loading. The system comprises a high temperature mechanical loading system, an internal pressure loading system and an online strain detecting system; the high temperature mechanical loading system is used for providing a high temperature environment and axial loads; the internal pressure loading system is used for providing gas of certain pressure for the interior of a pipeline of a sample to form internal pressure loads, and an unloading valve is arranged for pressure discharging; a high-temperature resistance strain gage is arranged on the surface of the sample in a spot welding manner and connected with a strain collecting instrument through a wire, the strain collecting instrument is connected to a computer, and the strain of the sample is detected online and calculated by measuring resistance value changes of the high-temperature resistance strain gage. According to the multiaxis creep test system, internal pressure loads and stretch loads can be loaded at the same time, the system is used for high temperature multiaxis creep behavior research of a material under the combined action of the internal pressure loads and the tensile loads, the amplitude of the internal pressure loads and the stretch loads is controlled, therefore, the influence of the multiaxial degree on the creep behavior of the material is studied, and the creep evolution law of the material in a multiaxial degree stress state is accurately revealed.