Self-consistent integral equations for the field distribution of the rasonant modes of virtual (real)concentrie resonators and semi-concentric resonators with circular mirrors were solved by comparing with that of plane parallel resonators. The amplitude distribution of field intensity on the mirror surfaces of the concentric or semi-concentric resonators are just the same as that of symmetric plane parallel resonators consisting of two identical plane mirrors seperated by a distance which equals to 2g2 times of the cavity length of concentric or semi-concentric resonators. The power loss per round trip of resonant mode of concentric or semi-concentric resonators just equals to that of per transit of the resonant mode of the plane parallel resonators mentioned above.