A secondary projection imaging system in a multi-beam apparatus is proposed, which makes the secondary electron detection with high collection efficiency and low cross-talk. The system employs one zoom lens, one projection lens and one anti-scanning deflection unit. The zoom lens and the projection lens respectively perform the zoom function and the anti-rotating function to remain the total imaging magnification and the total image rotation with respect to the landing energies and/or the currents of the plural primary beamlets. The anti-scanning deflection unit performs the anti-scanning function to eliminate the dynamic image displacement due to the deflection scanning of the plural primary beamlets.