The invention discloses a liquid bottle liquid quantity detection system applicable to a chemiluminescence immunoanalyzer and an application method of the liquid bottle liquid quantity detection system. Liquid quantity detection in a container can be conducted based on a capacitance detection principle, a probe coated with a ceramic material is assembled in a substrate bottle as an electrode, a metal plate is installed at the bottom of the bottle as the other electrode, the electrodes are connected to a voltage-controlled oscillator as oscillator capacitance input, the output end of the voltage-controlled oscillator is connected with a schmitt trigger to shape the waveform of a capacitance change signal, the shaped waveform is taken as a timer external clock source, and by calculating a timer value per unit time, a pulse frequency per unit time is calculated; the pulse frequencies in the liquid and liquid-free states are calculated, and then the reasonable frequency can be selected asa judgment threshold; and later, when the frequency exceeds the threshold, no liquid in the container is determined, the corresponding alarming prompting and other processes are executed, the condition of inadequate monitoring of the liquid quantity state of substrate liquid is avoided, and the accuracy of test results is ensured.