The invention relates to thermosetting acrylic resin for a powder coating. The thermosetting acrylic resin is prepared from the following raw materials in parts by mass: 4-14 parts of an initiator, 110-280 parts of soft monomers, 400-570 parts of hard monomers, 192-450 parts of functional monomers, and 1-8 parts of a molecular weight regulator, wherein the soft monomers refer to acrylic acid alkyl ester compounds, and the hard monomers refer to methacrylate, styrene, or compounds of derivatives of methacrylate and styrene. The acrylic resin contains epoxy functional groups and hydroxyl functional groups simultaneously, wherein the epoxy equivalent is 570-630g/mol and the hydroxyl value is 40-50mgKOH/g; the acrylic resin can react with various substances such as carboxyl, amidogen and isocyanate and can be used for powder coating. A coating film, which is formed after the thermosetting powder coating prepared from the acrylic resin in combination with other materials is sprayed, has excellent weather resistance, good leveling performance, outstanding surface hardness, and high glossiness, durability and decorating performance; the powder coating can be used for indoor or outdoor metal sectional materials or building materials. The thermosetting acrylic resin can substitute for TGIC (triglycidyl isocyanurate) to a certain extent so as to avoid the use of the toxic substances.