Combustion characteristics of B/BaCrO₄ delay composition were obtained by the technique of high speed camera. Results show that there exist the pulsed combustions and gas flow in the combustion process of B/BaCrO₄ delay composites. The condensed phases of products depend on the content of B,in which the phase is melted drops at lower content of B,but layered substances at higher content of B. When the different pressure of the composition surface is stronger than the stress strength of the solid products,the solid products will be pulled from the composite surface and flow with the gas. The thickness of layered substance of 14% B was 1.2 mm,and the blowed periods of layered substance of 14% B was 17.8 ms. The burning rate of B/BaCrO₄ delay composites increase with the content of B in the range of 8%-16%.