To investigate the potential risk of electromagnetic exposure, systematic studies on the bioeffects caused by single-frequency electromagnetic fields have been carried out with plenty of achievements.However, the bioeffects caused by multiple-frequency fields still need to be further studied. In the resent work, we constructed a dual-sourced irradiation system to allow two microwaves simultaneously incident from two perpendicular directions. Subsequently, the influence of the number of pulses on the blood, brain, testis, heart, and liver tissues of rats under the simultaneous irradiation of S-band and C-band pulsed microwaves was studied, and compared to that caused by the single-sourced exposure with the same electromagnetic exposure dose. The results showed that when the amplitude of the space electric field intensity was 44.84 kV/m and the number of the pulses was 2, 5, 20 and 200, the blood routine, testosterone, alanine aminotransferase and aspartate aminotransferase content of rats in the irradiation groups did not change significantly compared with the control group and sham group (p>0.05). The nuclear area in the brain, heart and liver of rats, as well as the Johnson score of the testis, has not significantly changed after the irradiation (p>0.05), and no pathological changes have been observed in these target tissues. The content of Bax in the above four tissues of rats in the irradiation groups increased nonlinearly with the increase of the number of pulses, which can be described as the non-thermal bioeffect that concerned the intensity of the electric field of the pulsed microwave. When the number of pulses is greater than 2, a significant apoptotic response was detected in the brain and testicle (p?0.05), while in the liver and heart the pulse number needs to be greater than 20 (p?0.05). This is mainly because the amplitude of the internal field of the brain and testicle (11.3 kV/m and 10 kV/m respectively) is higher than that of the liver and heart (5.73 kV/m and 5.33 kV/m respectively). Under the same electromagnetic exposure dose, there was no difference between the SC combined irradiation and the S or C individual-irradiation (p>0.05).