Abstract: Objective To observe the repeated +Gz exposure induced damage to heart, brain, kidneys and aorta in rats with spontaneous hypertension (SH). Methods Fourteen SH rats and 14 Wistar Kyoto rats (WKY) at the age of 8 weeks were randomly divided into SH +Gz exposure group， SH control group， WKY +Gz exposure group and WKY control group (7 in each group). The rats were exposed to +5 Gz/10 s, +9 Gz/10 s, +5 Gz/10 s, +9 Gz/10 s, +5 Gz/10 s and +9 Gz/10 s respectively by simulating air combat maneuver (SACM), which were repeated after the rats had a 20 min rest, total for 7 days. Samples taken from the heart, brain, kidneys and aorta of the rats at the end of exposure were stained with HE and observed under light microscope. The left ventricular mass index (LVMI) was measured. Results The LVMI was significantly higher in SH rat groups than in WKY rat groups (P＜0.01), and was significantly higher in SH +Gz exposure group than in SH control group. No significant target organ damage was observed in WKY +Gz exposure group and WKY control group under optical microscope. The damage to cardiac muscle, kidneys and cerebral cortex was severer in SH +Gz exposure group than in SH control group although it was observed both in the two groups. Conclusion +Gz exposure can aggravate the damage to target organs in SH rats.