In order to further study the motion characteristics and motion process of staggered bubbles, the VOF (volume of fluid) method in the OpenFOAM open source fluid dynamics software was used to simulate the double bubble rising behavior at different spaces and off-set distances under 3-D conditions. The effects of double bubble space and off-set distance on flow field, velocity field, and bubble morphology were analyzed. The results shown that four swirls with different sizes existed at two sides of two bubbles before the two bubbles moved and coalesced into one, and the swirl on the left of the lower bubble had a small influential range. Whereas both sides of which two big swirls formed and increased with off-set distance and the influential range of the left swirl increased, after two bubbles coalesced into one. The space and off-set distance of two bubbles affected their morphology during their rising behavior and coalescence. The off-set distance of the lower bubble increased, and the increment of their top velocity decreased for a constant bubble distance.