The utility model relates to a casting type voltage transformer which comprises a transformer shell and a secondary wiring terminal, wherein the secondary wiring terminal is exposed outside the transformer shell; a dust cover is covered on the periphery of the secondary wiring terminal, a wire outlet which is used for a secondary wire to pass through to be connected with the secondary wiring terminal is formed in the dust cover, and the dust cover is fixedly installed on the transformer shell; and a wire outlet sheath which is used for sealing the secondary wire is installed on the wire outlet in a clamped way. According to the casting type voltage transformer, after the dust cover is covered on the periphery of the secondary wiring terminal of the existing transformer, dust in the operating environment can be greatly prevented from dropping into the wiring terminal, and therefore, the dust cover has the effect of preventing terminal short circuit due to large dust deposition.