The extraction of motion regions and analysis of flicker are carried out separately in flame detection usually. A novel method is proposed here. Flicker of flame is detected while the motion regions are extracted. Firstly, candidate fire regions were detected based on Ohta color space with a color model of flame. Then, the motion regions with flicker frequency feature were extracted according to the degree and times of changes over a period at a certain position. Finally, the status whether the connected region is in flames or not was determined according to the intersection between the flame color region and the motion region. Experimental results show that the proposed method can ignore the regions which do not have the feature of flame flicker after the motion regions were extracted.It also performs well with high flame detection rate and lower false detection rate even if the motion region is incomplete.