Indoor air pollutants were monitored in 138 households in urban Xi'an that were recently decorated, and the concentrations of formaldehyde, total volatile organic compounds (TVOC), amines, benzene, methylbenzol, xylene, and radon were monitored in the bedrooms, sitting rooms, dinning rooms, kitchens, bathrooms, and studies of the houses. The most seriously elevated pollutants were TVOC and formaldehyde, whose rates exceeded standards by 69.8% and 60.8%, respectively. Ammonia was 13.2% above the standard, and xylene was 8.7% above the standard. The level of radon in 100% of the rooms was below the standard. Only for formaldehyde were there statistically significant differences in concentrations in the sitting room, bedroom, and study (P < 0.05). Concentrations of TVOC, amines, and xylene were positively related to the concentration of formaldehyde in the same room. The concentrations of the major pollutants in summer were highest and had a statistically significant difference with those in other seasons. TVOC and formaldehyde were the most serious pollutants indoors after decorating in an urban area of Xi'an. The concentrations of formaldehyde in the sitting rooms were different than in other types of rooms. Formaldehyde can be a representative of the levels of pollutants indoors; rooms with a higher concentration of formaldehyde tend to have higher levels of other pollutants. In addition, pollutants in the decorated rooms have a strong positive dependence on the monitoring seasons. Summer was the peak time of indoor pollutant levels. Households should pay extra attention to ventilation and take other effective measures to avoid health problems caused by indoor air pollutants.