A laser liquid level detection device is provided with linear optical magnification of a curved minor. The device includes a laser device, a CCD detecting device having a curved mirror and a CCD sensor and signal processing devices disposed in the laser device and the CCD detecting device. The laser device emits a laser beam to a surface level of a liquid, which reflects the beam to the CCD detecting device, and the curved mirror directs the reflected beam onto the CCD sensor. The shape of the curved mirror is determined by a polynomial curve function so as to linearly magnify a change in a height of the surface when the bounced beam reaches the CCD sensor. The liquid level detection device enables the position of the surface level of the liquid to be detectable in real time with high accuracy.