Acidic semi-bright tin plating solution and preparation method thereof

The invention discloses an acidic semi-bright tin plating solution and a preparation method thereof, and belongs to the field of material surface treatment. The solution disclosed by the invention comprises the following components with the following contents: 20-40g/L of stannous sulphate, 80-110mL/L of sulphuric acid, 0.1-0.5g/L of benzalacetone, 2-4mL/L of OP-10, 1.5-3mL/L of NP-10, 0.9-1.5g/L of sodium benzoate, 0.1-0.25g/L of nicotinic acid, 1-4g/L of gelatine, 2-3g/L of ferrous sulphate, 0.5-1g/L of ascorbic acid, 0.5-1g/L of antimony potassium tartrate and the balance water. The plating solution disclosed by the invention has high dispersion capacity and covering capacity, wide working temperature range and cathode current density range, high plating layer weldability, and a high binding force; and moreover, carcinogenic substances beta-naphthol and toxic aldehydes are not added, so that the plating solution is harmless to human body and environment, and capable of reducing a cost.