The invention belongs to the technical field of electric heating, and solves the problems that steam can not be effectively controlled in the prior art and energy is wasted. A boiler for boiling coffee by water comprises a pot body (3) and an electric heater (39) arranged on the pot body (3), the electric heater (39) is connected between a power supply end (8) and a power supply end (9), a detachable sealing ring (20) is arranged in an upper end port of the pot body (3), the boiler is provided with a connecting tube (30) capable of being inserted into a hole of the sealing ring (20), the other end of the connecting tube (30) is provided with a bamboo steamer (31), the boiler is provided with a funnel (21) capable of being inserted into the hole of the sealing ring (20), and a filter screen (23) is arranged in a leak (22) of the funnel (21). The boiler has the advantages of few parts, simple structure, easy replacement and operation, and multiple functions.