Objective To investigate the biological impacts of cell apoptosis and cell cycle caused by long term 900MHz electromagnetic radiation (EMR),which is crucial for further research of biological impacts induced by electromagnetic radiation. Methods NIH/3T3 cells were divided into Sham and Expo groups. The Expo group was exposed by 900MHz EMR at an average SAR of 4.0W/kg for 2 hours per day, lasting respectively 4, 7, 10 and 12days. The Sham group was cultured with no exposure. The cells were collected for cell apoptosis and cell cycle detection by flow cytometry (FCM) detection. Results The data indicated that 900MHz EMR apparently induced both early and late apoptosis in NIH/3T3 cells and 900MHz EMR could block NIH/3T3 cell cycle progression after 12-day exposure. The S phase got arrested after 12-day exposure. Conclusions After exposure to 900MHz EMR for 12days at average SAR of 4.0W/kg, obvious cell apoptosis was found in the whole progression of exposure. The effects on cell cycle were not clearly found until the cells were exposed to 900MHz EMR for 10days.