Depth measuring device for foundation pit monitoring and measuring method thereof

The invention discloses a depth measuring device for foundation pit monitoring, which comprises a fixed plate, a monitoring host is mounted on the fixed plate, a fixed cylinder is obliquely mounted on the fixed plate, an adjusting rod is slidably inserted in the upper end of the fixed cylinder, and a measuring instrument is fixedly embedded in one end, away from the fixed cylinder, of the adjusting rod; the invention further discloses a measuring method for measuring the depth of the foundation pit by adopting the measuring device. The measuring method comprises the following steps: assembling, stretching and aligning; scanning measurement is controlled; calculating measurement data; and outputting a measurement result. The measuring instrument is arranged above the foundation pit for global monitoring, two-dimensional plane depth measurement of the bottom of the foundation pit is achieved through transverse scanning measurement and longitudinal rotation intermittent measurement of the measuring instrument, m