Abstract: Based on the bench-scale opposed multi-burner（OMB） gasifier, impinging flame height and flame pulsation frequency were studied by industrial high speed camera combined with lateral high temperature endoscope. A new approach for flame image segmentation based on the pseudo-color enhancement was proposed. Industrial high resolution camera and top high temperature endoscope were applied to verify the results. In the laboratory operation conditions, with the increase of oxygen carbon atom ratio（O/C）, the impinging flame height is increased and a turning point appears at O/C of 1.8. The increase of diesel flow rate results in a relative obvious rise of flame height. Both the increase of O/C and diesel flow rate diminish the fluctuation range of flame height. The pulsation frequency of flame height is centralized in low frequency area. The characteristic peaks locate within 10 Hz, and there is a characteristic peak near 3 Hz for all the conditions. With the increase of O/C or diesel flow rate, the amplitude of characteristic peaks is reduced.