The utility model provides an optical detection device for keeping watch on first phenomenon of cigarette suction process decline, includes smoking machine holder, cigarette and some firearm, the characteristic is: the side is equipped with an optical sensor who is used for keeping watch on burning awl and adjustable horizontally at the cigarette, and the removal orbit of this sensor is parallel with cigarette the central axis, and the travel rate keeps the unanimity with cigarette combustibility rate, and optical sensor passes through the data transmission line and is connected with data processor. Surface temperature through detector measurable quantity cigarette suction in -process burning awl, surface temperature data transmission to computer is bored in burning through the data line will obtain, just can judge whether the cigarette takes place first phenomenon or make the judgement whether cigarette reachd the burning terminal point, when missing settlement fire end line, test burning awl surface temperature then judges and takes place first phenomenon for the cigarette if being less than 200 DEG C, remove the fire end line and test the temperature when being greater than 200 DEG C when the sensor, judge that this experiment finishes, be that the cigarette does not take place first phenomenon.