The master equation of a nonresonant two-mode laser in three level atomic system with equal detune for each mode is deduced. The influences of the detune over the laser operation are discussed. It is found that the gain and saturation coefficients are reduced by factors L and L2 separately. The influence of the detune is appreciable at slightly above the threshold operation and is fading away far above. The effect of the two-photon process is comparatively enhanced in detune case.