A pipe ML plug with fluid opening includes a main pipe portion, a rubber tube portion, a lower fixer, and an upper fixer. The rubber tube portion is disposed around a length portion of the main pipe portion and at the lower end of the main pipe portion, has a second inner diameter and a second outer diameter and extending straight for a second length, has a lower end and an upper end, and increases a blocking diameter when compressed lengthwise. The lower fixer and the upper fixer are configured for fixing a distance therebetween, so as to press the rubber tube portion lengthwise from both of the lower and upper ends to a specific length and thus to make the rubber tube portion bulge to a specific diameter, so that the bulged rubber tube portion blocks and seals an external pipe from inside.