Home environment is suggested to be an essential influencing factor for asthma development or asthma exacerbation. However, the association between home environment and childhood asthma among preschool children in the hot humid subtropical region in South China is unclear. We investigated doctor-diagnosed asthma in preschool children due to the parental perception of odors in homes. A total of 1946 children aged from 3 to 6 years from 22 kindergartens in Foshan were randomly recruited for this study in May 2016. The associations among childhood asthma, indoor environment and parental perceptions of odors were examined by using logistic regression model in terms of odds ratio (OR) and 95% confidence interval (CI). Parental atopy had the highest risk for childhood asthma with odds ratio = 6.007 (95% CI: 2.369–15.231). Parental perception of dry air significantly increased asthma with odds ratio = 1.284 (95% CI: 1.027–1.606). The parental perceptions of odors were strongly related with new furniture at home. We conclude that parental perception of dry air is a risk factor for the increase of childhood asthma in the present study. Hence, our study indicates a need to control the household humidity level and reduce the usage of new furniture, in order to reduce the risk of childhood asthma in South China. Display omitted •We addressed the indoor environmental health effect in subtropical South China.•Parental perception of dry air significantly associated with childhood asthma.•We found high correlation between parental perceptions of dry air and new furniture.•Prevalence of asthma in Foshan is lower than most cities in China.