A liquid piezometer comprises a transparent tube and a pressure intensity sensing box communicated with the transparent tube, wherein the pressure intensity sensing box is provided with a rubber membrane. The liquid piezometer is characterized in that the transparent tube is a bendable rubber tube, of which the inner diameter is smaller than 3 mm; the opening section of the rubber tube is vertically fixed to a panel; the panel is provided with scales for indicating the magnitude of the pressure intensity; and the pressure intensity sensing box is provided with a liquid inlet hole and is provided with a sealing soft plug. A base is fixedly arranged under the panel, and the base is provided with a placing box for placing the pressure intensity sensing box and the rubber tube. The beneficial effects are that coloured liquid (such as red ink) is filled to the pressure intensity sensing box and the transparent rubber tube through the liquid inlet hole, the hole is covered with the soft plug, and a syringe needle pierces through the soft plug to increase and decrease the coloured liquid, so that liquid level in the flexible pipe can be accurately adjusted to the zero graduation level; when the pressure intensity sensing box is put into the liquid to be measured, the rubber membrane is pressed, and the coloured liquid is pressed to rise in the transparent rubber tube, so that direct reading can be realized without calculating, and convenient usage is achieved; and by utilizing the transparent rubber tube, of which the inner diameter is very small, pressure intensity value in the liquid can be amplified, so that high measurement accuracy and high visibility are achieved.