The present invention discloses an A/D converting circuit with an inverse proportion characteristic physical quantity, which comprises an analog signal input circuit (1), a standard signal generator (2), an inverse proportion amplifying circuit (3), a timing pulse generator (9), a control signal generating circuit (6) and a gate circuit (7). The present invention is characterized in that the output end of the analog signal input circuit is connected with the input end of an inverse proportion amplifying circuit; the inverse proportion amplifying circuit receives an analog signal output by the analog signal input circuit and outputs the analog signal to a timing pulse generator after carrying out inverse proportion amplifying; the timing pulse generator converts an analog amplifying signal into a timing pulse and outputs the timing pulse to a control signal generating circuit; the control signal generating circuit outputs a gate control signal to agate circuit and simultaneously outputs a latch signal as well as a resetting signal to an external counting latch display circuit; the gate circuit outputs a count pulse signal to the external counting latch display circuit. The circuit of the present invention can be broadly applied to automatic detecting and automatic control systems.