Based on the flow characteristics of ramjet combustion chamber, combustion characters match of the flameholder and injectors is investigated by means of photography of using OH spontaneous radiation，and the two-phase flow numerical simulation. The influence of distance between the flameholder and the injectors on the fuel-air equivalence ratio distribution behind the flameholder is analyzed. The experiment results indicate that the space between the flameholder and injectors has signiticant influence on the reaction flow. When the space between the flameholder and injectors increased, the flame was closed to flameholder. And the flame flashed back when the velocity of air was low. when the space between the flameholder and injectors shortened, the flame flash back could avoided and the lift-off distance of the flame became small. The flame located close to the flameholder was due to improved vaporization and mixing at a big space between the flameholder and injectors.