The invention discloses a fiber-felt-reinforced composite material solar energy assembly frame and a preparation method thereof and aims to solve a problem of poor strength of a solar energy assembly frame structure in the prior art. In the invention, two solar energy assembly frames are jointed to each other to form a regular rectangular outer side, wherein the two solar energy assembly frames can be produced at the same time. Meanwhile, during a moulding process, the external side of unidirectional fiber bundles arranged in a preset shape is wrapped by fiber felt, and then the solar energy assembly frame is sent to a heating die for pultrusion. By means of cooperation with a pulling apparatus at the outer side and a cutting machine for cutting the material, the required solar energy assembly frame is formed. By means of addition of the continuous fiber felt at the outer side, the transversal strength of the solar energy assembly frame can be enhanced so that the solar energy assembly frame is excellent in comprehensive performances. By means the production of the two frames at the same time, the preparation method is increased in production efficiency, is simplified in processes and can promote an application of the composite material in photovoltaic field.