With the improvement of the living standards of people, the effects of indoor air quality on the health of people, such as Sick Building Symptom, have been generally attended. This paper explains the effects of indoor air quality on work and product efficiency in several aspects: (1)the effects of indoor air quality on the physical health of indoor people. Indoor air pollutants have the most important impacts on indoor people, such as volatile organic compound, formaldehyde, and so on, which cause the impairment of the physical health of people, the decrease of work efficiency and the increase of absence and the medical expenditure. The harm of single indoor air pollutant on health has been well researched, but the long-term and potential effects of several indoor air pollutants are imperceptible but greater, and need further study. (2)the effects of indoor air quality on the spiritual health of indoor people. The fidget, lethargy and the absence of responsibility of people who generally engaged in working indoors are connected with the decrease of indoor air quality. This paper overcomes the shortcomings and limitations of conventional assessment methods, and takes objective and subjective methods to assess it synthetically, taking in count of personal data of the researched. (3)the effects on the efficient operation of indoor machines. The requirements on indoor air quality are different, determined by the types of indoor machines. When the requirements are attended, it is more important to consider the effects of indoor air quality on operators in order to operate machines efficiently. This paper indicates that there is intimate relation between indoor air quality and work efficiency, leading to vast loss in absence and medical expenditure, and suggests several methods to improve indoor air quality.