To avoid the effect of falling body rotation on measurement accuracy for free-fall absolute gravity measurement based on optical interferometry, a novel method by using two interferometers was proposed. Firstly, the effect mechanism of falling body rotation on absolute gravity measurements was introduced and a data fusion method using data derived from an absolute gravimeter with two simultaneously measured interferometers was presented. Then simulation experiments were carried out according to a preset gravity value, the initial perpendicular height difference between the optical center (OC) and the center of mass (COM) in the upper and lower interferometer reflecting prisms in falling body, the randomly generated sequences of rotation angular velocity of falling body and the gravity measurement deviation caused by vibration for the upper and lower interferometer, respectively. The experimental results show that gravity deviation and the standard deviation obtained by data fusion processing from double interferometers with the vertical distance between OC and COM of 2.5 mm are about 0.5 μGal and 0.3 μGal, respectively, which are consistent with that of the existing method by strictly adjustment of the COM of fall body. By properly choosing the distance of OC to COM for the upper and lower prisms, the effect of rotation can be better reduced. When the distance of the OC to the COM is designed to be ±3 mm, the gravity value deviation calculated from double interferometer data fusion is less than 1μGal, which meets the requirements of some measurement fields for precise gravity measurement.