The invention discloses a general-purpose gasoline engine, comprising a cylinder block, a cylinder head main body (1), and an intake passage (12) and an exhaust passage (11) arranged on the cylinder head main body (1); an intake valve (5) is arranged on the cylinder head main body (1) correspondingly to the intake passage (12), an exhaust valve (9) is arranged correspondingly to the exhaust passage (11), the intake valve (5) is correspondingly provided with an intake rocker arm (8) and an intake push rod, the exhaust valve (9) is correspondingly provided with an exhaust rocker arm (2) and an exhaust push rod, a combustion chamber surface (13) is formed on the inner side of the cylinder head main body (1), and the combustion chamber surface (13) is of a spherical structure or an arch structure formed of smooth curves; the part of the combustion chamber surface (13) between the intake valve (5) and the exhaust valve (9) forms a nose bridge region (14), and a through air-cooling passage (10) is arranged on the cylinder head main body (1) on the outer side of the nose bridge region (14). The general-purpose gasoline engine in the invention is beneficial to the mixing of combustion gases and has excellent cooling efficiency.