A compound green-energy purification device includes a casing having a water inlet port and a gas outlet port, a filtration module arranged in the casing and includes a first filtration assembly and a second filtration assembly, an electrolysis unit arranged in the casing, and a separation base arranged in the casing and located between the filtration module and the electrolysis unit. The separation base includes a pipe and at least one hole formed therein such that the hole is located in a bottom of the separation base. Water is supplied through the water inlet port and flows through the hole of the separation base into the electrolysis unit to allow the electrolysis unit to heat and convert the water into steam, which moves through the pipe, the first filtration assembly, and the second filtration assembly so as to separate the water and the gas from each other.