The invention provides a tester for composite voltage breakdown characteristic of an oilpaper insulation structure in temperature gradients, and the tester is mainly used for research on the DC voltage breakdown characteristic of the oilpaper insulation structure in different temperature gradients in power enterprises, scientific research institutions, colleges and the like. The tester comprises a high-voltage power supply system, a temperature gradient circulation maintaining device and an automatic detection recording device. Different AC/DC composite voltage breakdown characteristic of the oilpaper insulation structure in the different temperature gradients can be researched, an AC/DC composite voltage generating power supply is more accurate, temperature gradient control is more standardized, the breakdown voltage and time are recorded automatically via a computer, and thus, a test result is more accurate.