A neutron diffraction investigation has been carried out on the trigonal La2O2S-type (hP5, space group P3¯ml, No. 164; also CaAl2Si2-type) YbMn2SbBi intermetallic compound. The YbMn2SbBi presents antiferromagnetic ordering below 138(3)K and ferrimagnetic ordering below 112(3)K. Between 138 and 112K, the magnetic structure of YbMn2SbBi consists of antiferromagnetically coupled ab-plane magnetic moments of the manganese atoms (D1d magnetic point group). Below 112(3)K, the ferromagnetic components of Yb and Mn begin to develop, and the magnetic structure of YbMn2SbBi becames the sum antiferromagnetic component with D1d magnetic point group and ferromagnetic one with C2 magnetic point group. The magnitude of Yb and Mn magnetic moments in YbMn2SbBi at 2K (MYb=3.6(2)μB, MMn=3.5(2)μB) correspond to the trivalent state of the Yb ions and tetravalent state of the Mn ions.