In this paper, the magnetic properties of p-type Zn1-xMnxO powders are reported. This are prepared from the decomposition of an oxalate precursor Zn1-xMnxC2O4.H2O. The oxalate precursor is obtained by coprecipitation of 50 ml of a 0.4mol/L aqueous solution of Zn and Mn acetates and the same volume of a 0.4 mol/L solution of oxalic acid. The mixed solution is stirred for 2h at room temperature. We added CH3COONH4 and In(NO3)3.H2O as p-type doped source (Zn:N:In=l:3:0.05 mol) to the solution with addition 3h stirring. The precipitate is then washed with distilled water and dried in air. The white powders obtained are then annealed in N2 at 500-800 K for 2h and finally turned moss yellow powder samples. The structure of the powder samples are studied by X-ray diffraction (XRD). All the observed lines from the XRD patterns show the ZnO structure without any hint of an impurity phase. With the increase of x, the peak position of Zn1-xMnxO shifts towards lower angles and the lattice constants a and c increase linearly, which means that the Mn2+ replaces well the Zn2+ to occupy the 2b crystallographic site.