We investigated the relationships among air quality indexes, such as the total number of bacteria "BAC", concentration of carbon dioxide "CO2", relative humidity "HUM", concentration of negative ion "NI" and opening time "TIM" in the environment of indoor public place. The data were divided into 3 levels based on its percentile and analyzed by correspondence analysis (ANACOR) and homogeneity analysis (HOMALS) in SPSS 8.0/10.0. Using these methods, we analyzed among 2 variables and their 3 levels, there were the relationships between BAC and CO2, CO2 and TIM, and BAC and TIM. When analyzing by HOMALS, among 3 variables and their 3 levels, there were some similar relationships: BAC, CO2 and TIM; BAC, CO2 and NI. The increase of CO2 and SAC were changed with TIM. The higher CO2 tended to increase BAC and to decrease NI. These results indicated under general conditions, CO2 can show the status of the air BAC. Increasing the ventilation and the relative humidity suitably may raise NI concentration and improve the air quality. Although the analytical results of the air quality by ANACOR and HOMALS are similar to that of chi-square test, ANACOR and HOMALS can be clearly shown in the plots with 2 or 3 axes. These two methods (ANACOR and HOMALS) may be useful to show the relationships among indoor air quality indexes more sensitively and directly