The change of reservoir dam’s piezometric level can reflect the dam’s internal structure, piezometric level number obtained by using detection technology can directly judge the interior defect, therefore, whether piezometric level detection is accurate or not is related to dam’s safety. After years’ research, the design scheme of integrating mechanics and electrics is put forward by combining with today’s popular single chip computer technology and digital measuring technology, which is the scheme that we adopt the digital detection technology to convert the water level into pulse digital signal directly and calculate the piezometric level according to the number of single pulse. It is necessary to develop a Piezometric Tube detector with teatures of high precision, high degree of automation and high speed of processing and acquisiting data and put it into use.