We had prepared Mn-doped ZnO and Li, Mn codoped-ZnO films with different concentrations using spin coating method. Crystal structure and magnetic measurements demonstrate that the impurity phases (ZnMnO3) are not contributed to room temperature ferromagnetism and the ferromagnetism in Mn-doped ZnO film is intrinsic. Interesting, saturated magnetization decreases with Mn or Li concentration increase, showing that some antiferromagnetism exists in the samples with high Mn or Li concentration. In addition, Mn0.05Zn0.95O film annealed in vaccum shows larger ferromagnetism than the as-prepared sample and more oxygen vacancies induced by annealing in reducing atmosphere enhance ferromagnetism, which supports the bound magnetic polaron model on the origin of room temperature ferromagnetism. (c) 2008 Elsevier B.V. All rights reserved.