The invention provides a smoke monitoring system. The smoke monitoring system comprises a smoke sensor, a smoke detecting unit, a converting unit, an analyzing unit and an alarming unit; the smoke sensor is used for detecting the concentration value of the smoke and alarming when the detected concentration value reaches the first preset threshold; the smoke detecting unit is used for obtaining the smoke concentration value detected by the smoke sensor; the converting unit is used for performing signal converting for the smoke concentration value obtained by the smoke detecting unit so as to obtain converting signal data; the analyzing unit is used for comparing the converting signal data with the second preset threshold data to obtain the comparison result and triggering the alarming unit to alarm when the comparison result meets the preset alarming condition. The invention also provides a smoke monitoring method applied to the smoke monitoring system. With the adoption of the system, the smoke condition in an electronic information system machine room can be monitored, and thus precise information devices in the electronic information system machine room can be effectively prevented from devastating damage in fire.