The invention relates to a novel energy-saving electromagnetic flowmeter for irrigation of agriculture and forestry, and aims at efficiently irrigating gardens and saving energy and water. The electromagnetic flowmeter comprises an ABS housing (571), a soft battery plug (572), a lithium battery (573), a PCB sealant assembly (574), a female tooth quick joint (575), two water sealing rings (576), a lower outer impeller cover (577), a magnetic sensing impeller (579), an upper outer impeller cover (578) and a male tooth quick joint (580); a screen window and a button opening which are formed in an outer sleeve are matched with a screen and a button which are arranged on the PCB sealant assembly (574); the lower outer impeller cover (577) is mounted in an inner pipe of the ABS housing (571), the magnetic sensing impeller (579) is movably arranged inside, and then the upper outer impeller cover (578) is assembled to the lower outer impeller cover (577), so as to form a flowmeter with a central shaft bracket. According to the electromagnetic flowmeter, various matching can be adopted, and therefore, the water can be comprehensively saved, and the batch export quality of the product can be increased.