The objective of this study was to investigate the effects of ultrasound‐guided injection of ultrasound contrast agents (UCAs) and the p53gene on the treatment of rats with breast cancer (BC). Assembly of the p53expression vector as well as that of a rat model with BC consisted of 200 successfully modeled rats randomly divided into 5 groups: p53gene introduction, p53gene introduction + ultrasound irradiation, p53gene introduction + UCAs, p53gene introduction + UCA + ultrasound irradiation, and UCA + ultrasound irradiation groups. Expression of p53was detected via quantitative real‐time polymerase chain reaction (qRT‐PCR), western blotting and immunohistochemical staining. In the p53gene introduction + ultrasound irradiation group, we observed increased tumor volume with blood flow signals around and necrotic tumor tissues with an inhibition rate of 36.30%, as well as higher expression of p53than that in the p53gene introduction group and p53gene introduction + UCA group. In the p53gene introduction + UCA + ultrasound irradiation group, tumor volume increased slightly with reduced blood flow signals and massive degenerative necrosis of tumor cells was identified with inhibition rate of 62.62%, and expression of p53was higher than that in the rest groups. Taken together, the key findings obtained from the present study elucidate that injection of p53gene and UCA microbubbles guided by ultrasound could increase the expression of p53, thus inhibiting the tumor growth in rats with BC.