The utility model relates to a vital capacity testing instrument, in particular to a clock-type comprehensive respiration tester which comprises a gas signal acquisition unit and a first signal processing unit. The gas signal acquisition unit comprises a gas sensor and an analog-to-digital (AD) conversion circuit. The output signal of the gas sensor is connected with the corresponding data input port of a single-chip microcomputer in the first signal processing unit through the AD conversion circuit. The single-chip microcomputer is provided with a corresponding input/output (I/O) port which is connected with a digital display module. The signal output end of the gas sensor is connected with a respiratory cycle acquisition unit. The respiratory cycle acquisition unit comprises an operational amplifier. The signal output end of the gas sensor is connected with the reverse input end of the operational amplifier. The output end of the operational amplifier is connected with one interruption input port of the single-chip microcomputer in the first signal processing unit through a switch. A light emitting diode (LED) lamp is connected between the output end of the operational amplifier and a ground terminal. The clock-type comprehensive respiration tester has the advantages of multiple functions, high practicability and convenience in use.